Add safepoints to GC methods in Heap. There is still stuff in
Heap::CollectGarbage which might work better or more precise in a global
safepoint. Be conservative here and move everything into the safepoint,
eventually we can start to move code out that is fine to run outside
the safepoint.

Bug: v8:10315
Change-Id: I656dfd72f032eff6f386cec63a02777506650aa7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2335192
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69228}