Instead of directly using the Heap class concurrent threads will use the
LocalHeap class for all heap operations.

Bug: v8:10315
Change-Id: Ie007abb5b914af7f2507c9e790f34baacbcdf588
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2096620
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66663}