Some global variables can be accessed from ractors

Some global variables should be used from non-main Ractors.
[Bug #17268]

```ruby
     # ractor-local (derived from created ractor): debug
     '$DEBUG' => $DEBUG,
     '$-d' => $-d,

     # ractor-local (derived from created ractor): verbose
     '$VERBOSE' => $VERBOSE,
     '$-w' => $-w,
     '$-W' => $-W,
     '$-v' => $-v,

     # process-local (readonly): other commandline parameters
     '$-p' => $-p,
     '$-l' => $-l,
     '$-a' => $-a,

     # process-local (readonly): getpid
     '$$'  => $$,

     # thread local: process result
     '$?'  => $?,

     # scope local: match
     '$~'  => $~.inspect,
     '$&'  => $&,
     '$`'  => $`,
     '$\''  => $',
     '$+'  => $+,
     '$1'  => $1,

     # scope local: last line
     '$_' => $_,

     # scope local: last backtrace
     '$@' => $@,
     '$!' => $!,

     # ractor local: stdin, out, err
     '$stdin'  => $stdin.inspect,
     '$stdout' => $stdout.inspect,
     '$stderr' => $stderr.inspect,
```

1 files changed, 4 insertions, 14 deletions

diff --git a/vm.c b/vm.c
index 879814a14b..ada33ae87b 100644
--- a/vm.c
+++ b/vm.c
@@ -3515,28 +3515,18 @@ Init_top_self(void)
     rb_define_alias(rb_singleton_class(rb_vm_top_self()), "inspect", "to_s");
 }
 
-static VALUE *
-ruby_vm_verbose_ptr(rb_vm_t *vm)
-{
-    return &vm->verbose;
-}
-
-static VALUE *
-ruby_vm_debug_ptr(rb_vm_t *vm)
-{
-    return &vm->debug;
-}
-
 VALUE *
 rb_ruby_verbose_ptr(void)
 {
-    return ruby_vm_verbose_ptr(GET_VM());
+    rb_ractor_t *cr = GET_RACTOR();
+    return &cr->verbose;
 }
 
 VALUE *
 rb_ruby_debug_ptr(void)
 {
-    return ruby_vm_debug_ptr(GET_VM());
+    rb_ractor_t *cr = GET_RACTOR();
+    return &cr->debug;
 }
 
 /* iseq.c */