Before we try to do ASI and fail with a generic error, we special case
for the await token in the failure case.

Bug: v8:6572, v8:6513
Change-Id: Ia050c98b5a5b20bc326f429a367635b8553e4112
Reviewed-on: https://chromium-review.googlesource.com/582210Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46885}