If there's a syntax error during iseq compilation then prism would leak
memory because it would not free the pm_parse_result_t.

This commit changes pm_iseq_new_with_opt to have a rb_protect to catch
when an error is raised, and return NULL and set error_state to a value
that can be raised by calling rb_jump_tag after memory has been freed.

For example:

    10.times do
      10_000.times do
        eval("/[/=~s")
      rescue SyntaxError
      end

      puts `ps -o rss= -p #{$$}`
    end

Before:

    39280
    68736
    99232
    128864
    158896
    188208
    217344
    246304
    275376
    304592

After:

    12192
    13200
    14256
    14848
    16000
    16000
    16000
    16064
    17232
    17952

Refactor out the same code from `rb_builtin_ast_value` and
`pm_builtin_ast_value.

There is an English word "vast".
This commit changes the name to be more clear name to avoid confusion.

This patch removes the `VALUE flags` member from the `rb_ast_t` structure making `rb_ast_t` no longer an IMEMO object.

## Background

We are trying to make the Ruby parser generated from parse.y a universal parser that can be used by other implementations such as mruby.
To achieve this, it is necessary to exclude VALUE and IMEMO from parse.y, AST, and NODE.

## Summary (file by file)

- `rubyparser.h`
  - Remove the `VALUE flags` member from `rb_ast_t`
- `ruby_parser.c` and `internal/ruby_parser.h`
  - Use TypedData_Make_Struct VALUE which wraps `rb_ast_t` `in ast_alloc()` so that GC can manage it
    - You can retrieve `rb_ast_t` from the VALUE by `rb_ruby_ast_data_get()`
  - Change the return type of `rb_parser_compile_XXXX()` functions from `rb_ast_t *` to `VALUE`
  - rb_ruby_ast_new() which internally `calls ast_alloc()` is to create VALUE vast outside ruby_parser.c
- `iseq.c` and `vm_core.h`
  - Amend the first parameter of `rb_iseq_new_XXXX()` functions from `rb_ast_body_t *` to `VALUE`
  - This keeps the VALUE of AST on the machine stack to prevent being removed by GC
- `ast.c`
  - Almost all change is replacement `rb_ast_t *ast` with `VALUE vast` (sorry for the big diff)
  - Fix `node_memsize()`
    - Now it includes `rb_ast_local_table_link`, `tokens` and script_lines
- `compile.c`, `load.c`, `node.c`, `parse.y`, `proc.c`, `ruby.c`, `template/prelude.c.tmpl`, `vm.c` and `vm_eval.c`
  - Follow-up due to the above changes
- `imemo.{c|h}`
  - If an object with `imemo_ast` appears, considers it a bug

Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>

This patch is part of universal parser work.

## Summary
- Decouple VALUE from members below:
  - `(struct parser_params *)->debug_lines`
  - `(rb_ast_t *)->body.script_lines`
- Instead, they are now `rb_parser_ary_t *`
  - They can also be a `(VALUE)FIXNUM` as before to hold line count
- `ISEQ_BODY(iseq)->variable.script_lines` remains VALUE
  - In order to do this,
  - Add `VALUE script_lines` param to `rb_iseq_new_with_opt()`
  - Introduce `rb_parser_build_script_lines_from()` to convert `rb_parser_ary_t *` into `VALUE`

## Other details
- Extend `rb_parser_ary_t *`. It previously could only store `rb_parser_ast_token *`, now can store script_lines, too
- Change tactics of building the top-level `SCRIPT_LINES__` in `yycompile0()`
  - Before: While parsing, each line of the script is added to `SCRIPT_LINES__[path]`
  - After: After `yyparse(p)`, `SCRIPT_LINES__[path]` will be built from `p->debug_lines`
- Remove the second parameter of `rb_parser_set_script_lines()` to make it simple
- Introduce `script_lines_free()` to be called from `rb_ast_free()` because the GC no longer takes care of the script_lines
- Introduce `rb_parser_string_deep_copy()` in parse.y to maintain script_lines when `rb_ruby_parser_free()` called
  - With regard to this, please see *Future tasks* below

## Future tasks
- Decouple IMEMO from `rb_ast_t *`
  - This lifts the five-members-restriction of Ruby object,
  - So we will be able to move the ownership of the `lex.string_buffer` from parser to AST
  - Then we remove `rb_parser_string_deep_copy()` to make the whole thing simple

[Feature #20205]

As a path toward enabling frozen string literals by default in the future,
this commit introduce "chilled strings". From a user perspective chilled
strings pretend to be frozen, but on the first attempt to mutate them,
they lose their frozen status and emit a warning rather than to raise a
`FrozenError`.

Implementation wise, `rb_compile_option_struct.frozen_string_literal` is
no longer a boolean but a tri-state of `enabled/disabled/unset`.

When code is compiled with frozen string literals neither explictly enabled
or disabled, string literals are compiled with a new `putchilledstring`
instruction. This instruction is identical to `putstring` except it marks
the String with the `STR_CHILLED (FL_USER3)` and `FL_FREEZE` flags.

Chilled strings have the `FL_FREEZE` flag as to minimize the need to check
for chilled strings across the codebase, and to improve compatibility with
C extensions.

Notes:
  - `String#freeze`: clears the chilled flag.
  - `String#-@`: acts as if the string was mutable.
  - `String#+@`: acts as if the string was mutable.
  - `String#clone`: copies the chilled flag.

Co-authored-by: Jean Boussier <byroot@ruby-lang.org>

This `st_table` is used to both mark and pin classes
defined from the C API. But `vm->mark_object_ary` already
does both much more efficiently.

Currently a Ruby process starts with 252 rooted classes,
which uses `7224B` in an `st_table` or `2016B` in an `RArray`.

So a baseline of 5kB saved, but since `mark_object_ary` is
preallocated with `1024` slots but only use `405` of them,
it's a net `7kB` save.

`vm->mark_object_ary` is also being refactored.

Prior to this changes, `mark_object_ary` was a regular `RArray`, but
since this allows for references to be moved, it was marked a second
time from `rb_vm_mark()` to pin these objects.

This has the detrimental effect of marking these references on every
minors even though it's a mostly append only list.

But using a custom TypedData we can save from having to mark
all the references on minor GC runs.

Addtionally, immediate values are now ignored and not appended
to `vm->mark_object_ary` as it's just wasted space.