The code accidentally jumped over the actual left-shift part when the
head of the array was the hole.

Bug: chromium:752722
Change-Id: I300a3ebcfafb07d6ecebc01fa57c66eb26f349ac
Reviewed-on: https://chromium-review.googlesource.com/603717Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47204}