Tweak a few names, remove a few GetIsolate calls, other minor
usability refactors.

It may be worth taking a closer look at the impl in the future,
currently the design choices don't seem ideal (see the added TODO
on top of the class).

Bug: v8:12161
Change-Id: Ib34e372aa58a30c68c9c5cdd0d1da0ec3e86717c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3560447Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Jakob Linke <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79687}