gc: change some atomic memory orderings #12808

Job	Run time
ruby-bench (--warmup=1 --bench=1)	15m 10s
make (check, --disable-yjit)	4m 29s
make (check, i686)	3m 9s
make (check, cppflags=-DVM_CHECK_MODE)	4m 43s
make (test-bundler-parallel, 50)	24m 43s
make (check, ubuntu-24.04, capi)	4m 49s
make (test-bundled-gems)	20m 11s
make (check, --enable-shared --enable-load-relative)	4m 37s
make-ibm	0s
Ubuntu result	2s
	1h 21m 53s

Provide feedback