1. Return null if the transition is out of bound.
2. Remove incorrect MAYBE_RETURN which is handled by the IsNothing check.


Bug: v8:11544
Change-Id: Ia54f68831120bd2460cb813464168b1a2c92da3d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3893595
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83171}