Also add tests for operators.

BUG=v8:5821

Change-Id: I76cfde94324c7f05de61cb60f26d5168da0a9aa5
Reviewed-on: https://chromium-review.googlesource.com/456500Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43922}