TracedGlobal is already cleared by V8 during garbage collections. It's
the embedders responsibility to clear the reference if it destroys the
underlying reference through other means.

Allow embedders to specify whether they want TracedGlobal to execute
clear on destruction via TracedGlobalTrait.

Bug: chromium:995684
Change-Id: Ieb10cf21f95eb97e01eff15d4fbd83538f17cf7c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1762007
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63289}