Avoid opt_aset_with optimization inside multiple assignment

	Previously, since the opt_aset_with optimization was introduced,
	use of the opt_aset_with optimization inside multiple assignment
	would result in a segfault or incorrect instructions.

	Fixes [Bug #21012]

	Co-authored-by: Nobuyoshi Nakada <nobu.nakada@gmail.com>

Introduce runtime flag for specifying the parser,

```
ruby --parser=prism
```

also update the description:

```
$ ruby --parser=prism --version
ruby 3.3.0dev (2023-12-08T04:47:14Z add-parser-runtime.. 0616384c9f) +PRISM [x86_64-darwin23]
```

[Bug #20044]

when the RUBY_FREE_ON_SHUTDOWN environment variable is set, manually free memory at shutdown.

Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
Co-authored-by: Peter Zhu <peter@peterzhu.ca>

This reverts commit 9b76c7fc89460ed8e9be40e4037c1d68395c0f6d.

Enable Prism using either --prism

    ruby --prism test.rb

or via env var

    RUBY_PRISM=1 ruby test.rb

The operands in each instruction needs to be pinned because if
auto-compaction runs in iseq_set_sequence, then the objects could exist
on the generated_iseq buffer, which would not be reference updated which
can lead to T_MOVED (and subsequently T_NONE) objects on the iseq.

fix [Feature #19572]

The `catch_except_p` flag is used for communicating between parent and
child iseq's that a throw instruction was emitted. So for example if a
child iseq has a throw in it and the parent wants to catch the throw, we
use this flag to communicate to the parent iseq that a throw instruction
was emitted.

This flag is only useful at compile time, it only impacts the
compilation process so it seems to be fine to move it from the iseq body
to the compile_data struct.

Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>

so that now shape can happily include gc.h