Also add self to AUTHORS.

Bug: v8:6504
Change-Id: Ia5bceee91c7589bc53198e69c5623f1a26918c02
Reviewed-on: https://chromium-review.googlesource.com/541718


Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#481038}