[PATCH] Fix refinement modification of method visibility in superclass

	Previously, this didn't work correctly, resulting in a
	SystemStackError. This fixes the issue by finding the related
	superclass method entry, and updating the orig_me in the
	refinement method to point to the superclass method.

	Fixes [Bug #21446]

	[PATCH] [Bug #21673] Fix resolving refined module-defined method

	A method defined in a module has no `defined_class`, use the ICLASS
	for it as the `defined_class`.

Previously, ruby2_keywords could be used on a method or proc with
post arguments, but I don't think the behavior is desired:

```ruby
def a(*c, **kw) [c, kw] end
def b(*a, b) a(*a, b) end
ruby2_keywords(:b)

b({foo: 1}, bar: 1)
```

This changes ruby2_keywords to emit a warning and not set the
flag on a method/proc with post arguments.

While here, fix the ruby2_keywords specs for warnings, since they
weren't testing what they should be testing.  They all warned
because the method didn't accept a rest argument, not because it
accepted a keyword or keyword rest argument.

[Backport #21402]

It used to quote only part of the method name because NUL byte in
the method terminates the C string:

```
(irb)> "abcdef".encode("UTF-16LE").bytes
=> [97, 0, 98, 0, 99, 0, 100, 0, 101, 0, 102, 0]
```

```
expected: /abcdef/
actual: warning: Skipping set of ruby2_keywords flag for a (method not defined in Ruby)\n".
```

[Feature #20912]

So that it doesn't get included in the generated binaries for builds
that don't support loading shared GC modules

Co-Authored-By: Peter Zhu <peter@peterzhu.ca>

The hash value of a Method must remain constant after a compaction, otherwise
it may not work as the key in a hash table.

For example:

    def a; end

    # Need this method here because otherwise the iseq may be on the C stack
    # which would get pinned and not move during compaction
    def get_hash
      method(:a).hash
    end

    puts get_hash # => 2993401401091578131

    GC.verify_compaction_references(expand_heap: true, toward: :empty)

    puts get_hash # => -2162775864511574135

* YJIT: Replace Array#each only when YJIT is enabled

* Add comments about BUILTIN_ATTR_C_TRACE

* Make Ruby Array#each available with --yjit as well

* Fix all paths that expect a C location

* Use method_basic_definition_p to detect patches

* Copy a comment about C_TRACE flag to compilers

* Rephrase a comment about add_yjit_hook

* Give METHOD_ENTRY_BASIC flag to Array#each

* Add --yjit-c-builtin option

* Allow inconsistent source_location in test-spec

* Refactor a check of BUILTIN_ATTR_C_TRACE

* Set METHOD_ENTRY_BASIC without touching vm->running

`me->defined_class` should be 0 for method entries of
Modules.

This patch checks this condition
and fix https://github.com/ruby/ruby/pull/11965#issuecomment-2448291790