We now have different mechanisms for black allocation, for regular
sized objects we will set all mark bits for the LAB. For large
objects we will set the mark bit when initializing that large page.

So when we reach this method, the object is already marked black.

Bug: v8:11708
Change-Id: Ie0f82f78eefe06a25103264098cc59a3ee46d20c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3817742
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82275}