The size is queried from the background thread to check whether
incremental marking should be started.

Bug: chromium:1292728
Change-Id: I60e0def5756b62ef2ae2d10cc76ce745f3aef308
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3440654
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78953}