The allocation step in FreeLinearAllocationArea may start incremental
marking and mark the area to be freed, which breaks the invariant
that all blocks in the free list are unmarked.

Bug: v8:10679
Tbr: dinfuehr@chromium.org
Change-Id: I23b92e402968361b57010a017b382747f7da673d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2282537Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68694}