[Bug #22002] Never pop when compiling branch predicate

	The value is always needed. Now prism emits the same instructions as parse.y for the added test case.

	`defined?`/`flip-flop` caused `argument stack underflow`, `and`/`or` segfaulted during runtime.

	class.c: rb_class_duplicate_classext also dup content of cvc_tbl

	[Bug #21952]

	Shallow copying the table result in the same memory being shared
	between multiple box, causing double free when one of the box
	is garbage collected.

	---

	class.c: Make cvc_tbl a managed object

	[Bug #21952]

	Solves the double-free or use after-free concern with boxes.
	Now entries can safely be used for copy-on-write.

	Also is likely necessary to make it save to read cvar from
	secondary ractors, as allowed since: ab32c0e690b805cdaaf264ad4c3421696c588204

	[PATCH] [Bug #22004] Fix short-circuited loop conditions

	[PATCH] Mark `$_` as box-dynamic to bypass Box gvar_tbl cache

	`$_` is updated through svar (rb_lastline_set), bypassing
	rb_gvar_set, so the Box gvar_tbl cache is never invalidated
	and returns a stale value. Call rb_gvar_box_dynamic so
	gvar_use_box_tbl() skips the cache.

	Fixes [Bug #21940](https://bugs.ruby-lang.org/issues/21940)

	[PATCH] Fix Box regexp match vars after non-match

	[PATCH] Use box_ready for $&, $`, $\', $+

	These variables have rb_gvar_readonly_setter, so box_ready is sufficient.
	Only $~ needs box_dynamic due to its custom match_setter.

	[PATCH] [Bug #21986] Fix location of numeric literal

	When checking for suffixes, do not flush the numeric literal token
	even if no suffix is found.

	[PATCH] [Bug #21985] Include the `-` in the negative numbers location

[Bug #22018]

ISeq returned by `RubyVM::InstructionSequene.load_iseq` weren't
handled by the coverage module.

Extends the @_init guard to def_method so that an ERB object created
via Marshal.load (which bypasses initialize) raises ArgumentError
instead of evaluating arbitrary source. def_module and def_class both
delegate to def_method and are covered by the same check.

Co-authored-by: Tristan Madani <TristanInSec@gmail.com>