[Bug #21144] Win32: Use Windows time zone ID if TZ is not set

	If the TZ environment variable is not set, the time zone names
	retrieved from the system are localized for UI display and may vary
	across editions and language packs for the same time zone.
	Use the time zone IDs that are invariant across environments instead.

	[Bug #21144] Win32: Convert the time zone name to the current locale

	The Windows time zone IDs provided by Microsoft as of 24H1 are ASCII
	only all, but the API itself is not impossible to set non-ASCII key
	name.  Prefer the current locale encoding for now until we move to
	UTF-8 including environment variables and command line arguments.

	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.

If one thread is reading and another closes that socket, the close
blocks waiting for the read to abort cleanly. This ensures that Ruby is
totally done with the file descriptor _BEFORE_ we tell the OS to close
and potentially re-use it.

When the read is correctly terminated, the close should be unblocked.
That currently works if closing is happening on a thread, but if it's
happening on a fiber with a fiber scheduler, it does NOT work.

This patch ensures that if the close happened in a fiber scheduled
thread, that the scheduler is notified that the fiber is unblocked.

[Bug #20723]

	[Bug #20342] Consider wrapped load in `main` methods

	Make io_fwrite safe for compaction

	[Bug #20169]

	Embedded strings are not safe for system calls without the GVL because
	compaction can cause pages to be locked causing the operation to fail
	with EFAULT. This commit changes io_fwrite to use rb_str_tmp_frozen_no_embed_acquire,
	which guarantees that the return string is not embedded.

Don't pin named structs defined in Ruby

	[Bug #20311]

	`rb_define_class_under` assumes it's called from C and that the
	reference might be held in a C global variable, so it adds the
	class to the VM root.

	In the case of `Struct.new('Name')` it's wasteful and make
	the struct immortal.

	Make Struct memory leak test faster

	[Bug #20311]

	It times out on some platform, so we can reduce iterations.
	On my machine it completes in 250ms and RSS grows 8X.

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.

rb_obj_setup: do not copy RUBY_FL_SEEN_OBJ_ID

	[Bug #20250]

	We're seting up a new instance, so it never had an associated
	object_id.

	proc.c: get rid of `CLONESETUP`
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	[Bug #20253]

	All the way down to Ruby 1.9, `Proc`, `Method`, `UnboundMethod`
	and `Binding` always had their own specific clone and dup routine.

	This caused various discrepancies with how other objects behave
	on `dup` and `clone. [Bug #20250], [Bug #20253].

	This commit get rid of `CLONESETUP` and use the the same codepath
	as all other types, so ensure consistency.

	NB: It's still not accepting the `freeze` keyword argument on `clone`.

	Co-Authored-By: Étienne Barrié <etienne.barrie@gmail.com>