For example, there is no need to do UncheckedCast<Object>(obj), if obj
is already of type Object.

Bug: v8:6949
Change-Id: I44278a023cb8741ead7b554569c66f412f01ffee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2737294Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73210}