ToSpaceContainsSlow is only from Heap:InSpaceSlow that is never used for
new space.
FromSpaceContains is never called.
ToSpaceContains is called from unittests and from Heap::Contains, and
replacing it wioth  NewSpace::Contains should keep things fast as that
one relies on a page flag.

Bug: v8:12612
Change-Id: I58d63a85fd66aa27f9c4a7794e21838a59aab3d0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3610447Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80228}