We clear the CFP first so that if a sampling profiler interrupts the current thread during `rb_ec_set_vm_stack`,
`thread_profile_frames` returns early instead of trying to walk the stack that's no longer set on the ec.

The early return in `thread_profile_frames` was introduced at eab7f4623fb.

Fixes [Bug #21441]

	Push a real iseq in rb_vm_push_frame_fname()

	Previously, vm_make_env_each() (used during proc
	creation and for the debug inspector C API) picked up the
	non-GC-allocated iseq that rb_vm_push_frame_fname() creates,
	which led to a SEGV when the GC tried to mark the non GC object.

	Put a real iseq imemo instead. Speed should be about the same since
	the old code also did a imemo allocation and a malloc allocation.

	Real iseq allows ironing out the special-casing of dummy frames in
	rb_execution_context_mark() and rb_execution_context_update(). A check
	is added to RubyVM::ISeq#eval, though, to stop attempts to run dummy
	iseqs.

	[Bug #21180]

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

	Use no-inline version `rb_current_ec` on Arm64

	The TLS across .so issue seems related to Arm64, but not Darwin.

	Fix use-after-free in ep in Proc#dup for ifunc procs

	[Bug #20950]

	ifunc proc has the ep allocated in the cfunc_proc_t which is the data of
	the TypedData object. If an ifunc proc is duplicated, the ep points to
	the ep of the source object. If the source object is freed, then the ep
	of the duplicated object now points to a freed memory region. If we try
	to use the ep we could crash.

	For example, the following script crashes:

	    p = { a: 1 }.to_proc
	    100.times do
	      p = p.dup
	      GC.start
	      p.call
	    rescue ArgumentError
	    end

	This commit changes ifunc proc to also duplicate the ep when it is duplicated.

Https://learn.microsoft.com/en-us/cpp/build/reference/zc-inline-remove-unreferenced-comdat?view=msvc-140
> If `/Zc:inline` is specified, the compiler enforces the C++11
> requirement that all functions declared inline must have a definition
> available in the same translation unit if they're used.

Add memory leak test for eval kwargs

	De-dup identical callinfo objects

	Previously every call to vm_ci_new (when the CI was not packable) would
	result in a different callinfo being returned this meant that every
	kwarg callsite had its own CI.

	When calling, different CIs result in different CCs. These CIs and CCs
	both end up persisted on the T_CLASS inside cc_tbl. So in an eval loop
	this resulted in a memory leak of both types of object. This also likely
	resulted in extra memory used, and extra time searching, in non-eval
	cases.

	For simplicity in this commit I always allocate a CI object inside
	rb_vm_ci_lookup, but ideally we would lazily allocate it only when
	needed. I hope to do that as a follow up in the future.

When a forked process was started in a thread, this would result in a
double-free during the child process exit.

    RUBY_FREE_AT_EXIT=1 ./miniruby -e 'Thread.new { fork { } }.join; Process.waitpid'

This is because the main thread in the forked process was not the
initial VM thread, and the new thread's stack was freed as part of
objectspace iteration.

This change also allows rb_threadptr_root_fiber_release to run without
EC being available.

Ractor's free iterates through its TLS keys so we need to keep this
memory available until after Ractors are freed.

Minimal reproduction:

    RUBY_FREE_AT_EXIT=1 ./miniruby -e rand