The new predicate indicates whether the backing store was created for
an ArrayBuffer or a SharedArrayBuffer. It is useful for some embedders.

Bug: v8:9380
Change-Id: I804063bb8c4c17815defd6538ce6a1b32f6a4531
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1873689
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64479}