Add clusterfuzz check to v8 auto-roll script and use CQ.

This adds a check step that makes sure there are no new issues when rolling into chromium.

It also checks the cq bit on roll upload.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/315133003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21996 ce2b1a6d-e550-0410-aec6-3dcde31c8c00