Revert "reuse open(2) from rb_file_load_ok on POSIX-like system"

This reverts commit 35136e1e9c232ad7a03407b992b2e86b6df43f63.

test-spec has been failing since this revision.

.github/workflows/compilers.yml:82
https://github.com/ruby/ruby/actions/runs/4276884159/jobs/7445299562

```
env:
  # Minimal flags to pass the check.
  default_cc: 'gcc-11 -fcf-protection -Wa,--generate-missing-build-notes=yes'
  optflags: '-O2'
  LDFLAGS: '-Wl,-z,now'
  # FIXME: Drop skipping options
  # https://bugs.ruby-lang.org/issues/18061
  # https://sourceware.org/annobin/annobin.html/Test-pie.html
  TEST_ANNOCHECK_OPTS: "--skip-pie --skip-gaps"
```

Failure:

```
  1)
  An exception occurred during: Kernel#require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:317
  Kernel#require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  2)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:330
  Kernel#require ($LOADED_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  3)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:535
  Kernel#require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  4)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:551
  Kernel#require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 9 : #<File:../code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  5)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:563
  Kernel#require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required ERROR
  LeakError: Closed file descriptor: 8
  Closed file descriptor: 9
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  6)
  An exception occurred during: Kernel.require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:317
  Kernel.require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  7)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:330
  Kernel.require ($LOADED_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  8)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:535
  Kernel.require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  9)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:551
  Kernel.require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 9 : #<File:../code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  10)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:563
  Kernel.require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required ERROR
  LeakError: Closed file descriptor: 8
  Closed file descriptor: 9
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  11)
  An exception occurred during: Kernel#require_relative with a relative path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:197
  Kernel#require_relative with a relative path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:4:in `<top (required)>'

  12)
  An exception occurred during: Kernel#require_relative with a relative path ($LOADED_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:205
  Kernel#require_relative with a relative path ($LOADED_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:4:in `<top (required)>'

  13)
  An exception occurred during: Kernel#require_relative with an absolute path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:399
  Kernel#require_relative with an absolute path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:277:in `<top (required)>'

  14)
  An exception occurred during: Kernel#require_relative with an absolute path ($LOAD_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:407
  Kernel#require_relative with an absolute path ($LOAD_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:277:in `<top (required)>'
```

1 files changed, 18 insertions, 28 deletions

diff --git a/load.c b/load.c
index 9025a89c87..0f8d63a37f 100644
--- a/load.c
+++ b/load.c
@@ -676,8 +676,7 @@ rb_provide(const char *feature)
 NORETURN(static void load_failed(VALUE));
 
 static inline void
-load_iseq_eval(rb_execution_context_t *ec, VALUE fname,
-                struct ruby_file_load_state *fls)
+load_iseq_eval(rb_execution_context_t *ec, VALUE fname)
 {
     const rb_iseq_t *iseq = rb_iseq_load_iseq(fname);
 
@@ -687,7 +686,7 @@ load_iseq_eval(rb_execution_context_t *ec, VALUE fname,
         rb_ast_t *ast;
         VALUE parser = rb_parser_new();
         rb_parser_set_context(parser, NULL, FALSE);
-        ast = (rb_ast_t *)rb_parser_load_state(parser, fname, fls);
+        ast = (rb_ast_t *)rb_parser_load_file(parser, fname);
         iseq = rb_iseq_new_top(&ast->body, rb_fstring_lit("<top (required)>"),
                                fname, rb_realpath_internal(Qnil, fname, 1), NULL);
         rb_ast_dispose(ast);
@@ -699,8 +698,7 @@ load_iseq_eval(rb_execution_context_t *ec, VALUE fname,
 }
 
 static inline enum ruby_tag_type
-load_wrapping(rb_execution_context_t *ec, VALUE fname, VALUE load_wrapper,
-              struct ruby_file_load_state *fls)
+load_wrapping(rb_execution_context_t *ec, VALUE fname, VALUE load_wrapper)
 {
     enum ruby_tag_type state;
     rb_thread_t *th = rb_ec_thread_ptr(ec);
@@ -720,7 +718,7 @@ load_wrapping(rb_execution_context_t *ec, VALUE fname, VALUE load_wrapper,
     EC_PUSH_TAG(ec);
     state = EC_EXEC_TAG();
     if (state == TAG_NONE) {
-        load_iseq_eval(ec, fname, fls);
+        load_iseq_eval(ec, fname);
     }
     EC_POP_TAG();
 
@@ -746,7 +744,7 @@ raise_load_if_failed(rb_execution_context_t *ec, enum ruby_tag_type state)
 }
 
 static void
-rb_load_internal(VALUE fname, VALUE wrap, struct ruby_file_load_state *fls)
+rb_load_internal(VALUE fname, VALUE wrap)
 {
     rb_execution_context_t *ec = GET_EC();
     enum ruby_tag_type state = TAG_NONE;
@@ -754,10 +752,10 @@ rb_load_internal(VALUE fname, VALUE wrap, struct ruby_file_load_state *fls)
         if (!RB_TYPE_P(wrap, T_MODULE)) {
             wrap = rb_module_new();
         }
-        state = load_wrapping(ec, fname, wrap, fls);
+        state = load_wrapping(ec, fname, wrap);
     }
     else {
-        load_iseq_eval(ec, fname, fls);
+        load_iseq_eval(ec, fname);
     }
     raise_load_if_failed(ec, state);
 }
@@ -765,10 +763,9 @@ rb_load_internal(VALUE fname, VALUE wrap, struct ruby_file_load_state *fls)
 void
 rb_load(VALUE fname, int wrap)
 {
-    struct ruby_file_load_state fls = { .filev = Qfalse };
-    VALUE tmp = ruby_find_file(FilePathValue(fname), &fls);
+    VALUE tmp = rb_find_file(FilePathValue(fname));
     if (!tmp) load_failed(fname);
-    rb_load_internal(tmp, RBOOL(wrap), &fls);
+    rb_load_internal(tmp, RBOOL(wrap));
 }
 
 void
@@ -820,7 +817,6 @@ static VALUE
 rb_f_load(int argc, VALUE *argv, VALUE _)
 {
     VALUE fname, wrap, path, orig_fname;
-    struct ruby_file_load_state fls = { .filev = Qfalse };
 
     rb_scan_args(argc, argv, "11", &fname, &wrap);
 
@@ -828,13 +824,13 @@ rb_f_load(int argc, VALUE *argv, VALUE _)
     fname = rb_str_encode_ospath(orig_fname);
     RUBY_DTRACE_HOOK(LOAD_ENTRY, RSTRING_PTR(orig_fname));
 
-    path = ruby_find_file(fname, &fls);
+    path = rb_find_file(fname);
     if (!path) {
-        if (!rb_file_load_ok(RSTRING_PTR(fname), &fls))
+        if (!rb_file_load_ok(RSTRING_PTR(fname)))
             load_failed(orig_fname);
         path = fname;
     }
-    rb_load_internal(path, wrap, &fls);
+    rb_load_internal(path, wrap);
 
     RUBY_DTRACE_HOOK(LOAD_RETURN, RSTRING_PTR(orig_fname));
 
@@ -965,8 +961,7 @@ rb_f_require_relative(VALUE obj, VALUE fname)
 typedef int (*feature_func)(rb_vm_t *vm, const char *feature, const char *ext, int rb, int expanded, const char **fn);
 
 static int
-search_required(rb_vm_t *vm, VALUE fname, volatile VALUE *path,
-                feature_func rb_feature_p, struct ruby_file_load_state *fls)
+search_required(rb_vm_t *vm, VALUE fname, volatile VALUE *path, feature_func rb_feature_p)
 {
     VALUE tmp;
     char *ext, *ftptr;
@@ -981,7 +976,7 @@ search_required(rb_vm_t *vm, VALUE fname, volatile VALUE *path,
                 if (loading) *path = rb_filesystem_str_new_cstr(loading);
                 return 'r';
             }
-            if ((tmp = ruby_find_file(fname, fls)) != 0) {
+            if ((tmp = rb_find_file(fname)) != 0) {
                 ext = strrchr(ftptr = RSTRING_PTR(tmp), '.');
                 if (!rb_feature_p(vm, ftptr, ext, TRUE, TRUE, &loading) || loading)
                     *path = tmp;
@@ -1022,7 +1017,7 @@ search_required(rb_vm_t *vm, VALUE fname, volatile VALUE *path,
         return 'r';
     }
     tmp = fname;
-    type = ruby_find_file_ext(&tmp, ft == 's' ? ruby_ext : loadable_ext, fls);
+    type = rb_find_file_ext(&tmp, ft == 's' ? ruby_ext : loadable_ext);
 #if EXTSTATIC
     if (!ft && type != 1) { // not already a feature and not found as a dynamic library
         VALUE lookup_name = tmp;
@@ -1108,7 +1103,7 @@ rb_resolve_feature_path(VALUE klass, VALUE fname)
 
     fname = rb_get_path(fname);
     path = rb_str_encode_ospath(fname);
-    found = search_required(GET_VM(), path, &path, no_feature_p, NULL);
+    found = search_required(GET_VM(), path, &path, no_feature_p);
 
     switch (found) {
       case 'r':
@@ -1168,7 +1163,6 @@ require_internal(rb_execution_context_t *ec, VALUE fname, int exception, bool wa
     VALUE realpaths = get_loaded_features_realpaths(th->vm);
     volatile bool reset_ext_config = false;
     struct rb_ext_config prev_ext_config;
-    struct ruby_file_load_state fls = { .filev = Qfalse };
 
     fname = rb_get_path(fname);
     path = rb_str_encode_ospath(fname);
@@ -1183,7 +1177,7 @@ require_internal(rb_execution_context_t *ec, VALUE fname, int exception, bool wa
         int found;
 
         RUBY_DTRACE_HOOK(FIND_REQUIRE_ENTRY, RSTRING_PTR(fname));
-        found = search_required(th->vm, path, &saved_path, rb_feature_p, &fls);
+        found = search_required(th->vm, path, &saved_path, rb_feature_p);
         RUBY_DTRACE_HOOK(FIND_REQUIRE_RETURN, RSTRING_PTR(fname));
         path = saved_path;
 
@@ -1206,14 +1200,10 @@ require_internal(rb_execution_context_t *ec, VALUE fname, int exception, bool wa
             else {
                 switch (found) {
                   case 'r':
-                    load_iseq_eval(ec, path, &fls);
+                    load_iseq_eval(ec, path);
                     break;
 
                   case 's':
-                    if (fls.filev != Qfalse) {
-                        rb_io_close(fls.filev);
-                        fls.filev = Qfalse;
-                    }
                     reset_ext_config = true;
                     ext_config_push(th, &prev_ext_config);
                     handle = (long)rb_vm_call_cfunc(rb_vm_top_self(), load_ext,