Add major GC reasons to GC.stat #9590

Job	Run time
cargo clippy	33s
cargo test	1m 12s
make (test-bundled-gems, --enable-yjit=dev)	24m 13s
make (yjit-bindgen, To fix: use patch in logs, --with-gcc=clang-14 --enable-yjit=dev --enable-zji...	4m 47s
make (check, --enable-yjit=dev, --yjit-call-threshold=1 --yjit-verify-ctx --yjit-code-gc, -T --yj...	16m 38s
make (check, RUSTC='rustc +1.58.0', 1.58.0)	9m 0s
make (check, --enable-yjit=dev)	13m 26s
YJIT Ubuntu result	3s
	1h 9m 52s

Provide feedback