(source_length - 1) can be overflowed, and cause OOB access when source_length
is zero. Thus, just do not operate setting if source_length is zero when
starting TypedArraySetFromOverlapping.

Bug: v8:6704
Change-Id: I5da60590c9a197eae96625a12720f6818b8c598a
Reviewed-on: https://chromium-review.googlesource.com/620452
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Reviewed-by: Franziska Hinkelmann <franzih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47430}