.. of the backing store, instead of continuing and silently attempting
to deref nullptr.

Bug: chromium:1198657
Change-Id: I82e51abc4d2f9dfe0de596b082a6f78089af7df8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2824438Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73949}