This CL covers simple ("simple") rest param cases.

BUG=v8:5516
R=vogelheim@chromium.org

Change-Id: I254c2eb81d759eb2ea2a3d5e7c46bcdc2ccef707
Reviewed-on: https://chromium-review.googlesource.com/440984Reviewed-by: Daniel Vogelheim <vogelheim@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43106}