Unused imports and some deprecation related updates.

Bug: v8:12785
Change-Id: Ia3998a75f0c3b83eef4134741c1bda5f3d49c6f4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3678840Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Liviu Rau <liviurau@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80883}