This patch handles C-style, as well as for-in/of loops. for-await loops
will be changed in a followup.

Bug: v8:6724
Change-Id: I264b8c2d41c0318e796839bf204f7d77b6d24dd8
Reviewed-on: https://chromium-review.googlesource.com/617410Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47404}