Incremental finalization previously used to rescan roots to avoid any
new work showing up in the atomic pause.

With concurrent marking we should be way faster in finalizing, so that
we can save ourselves this work. In particular, if we finalize in the
same JS execution we would be doubling work as the atomic pause
anyways needs to rescan all roots.

Bug: v8:12775
Change-Id: I58a5a931da72c8d5c8aee4cd5dad4512954668b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3570427Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79784}