partially merge revision(s) 119697f6,4a627dbd: [Backport #18014]

	[Bug #18014] Fix rb_gc_force_recycle unmark before sweep

	If we force recycle an object before the page is swept, we should clear
	it in the mark bitmap. If we don't clear it in the bitmap, then during
	sweeping we won't account for this free slot so the `free_slots` count
	of the page will be incorrect.
	---
	 gc.c | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)

	[Bug #18014] Fix memory leak in GC when using Ractors

	When a Ractor is removed, the freelist in the Ractor cache is not
	returned to the GC, leaving the freelist permanently lost. This commit
	recycles the freelist when the Ractor is destroyed, preventing a memory
	leak from occurring.
	---
	 gc.c          | 116 +++++++++++++++++++++++++++-------------------------------
	 internal/gc.h |   6 +++
	 ractor.c      |   3 ++
	 ractor_core.h |   5 +--
	 4 files changed, 64 insertions(+), 66 deletions(-)

Co-authored-by: Peter Zhu <peter@peterzhu.ca>