R1:3078778fc064

Support more aliases of "Test Plan" in commit messages

Summary: Add support for "tests", "testplan" and "tested" as alias of "Test Plan".

Test Plan: Created a diff with test plan specified in "tests".

Reviewers: csilvers, btrahan

Reviewed By: csilvers

CC: aran

Differential Revision: https://secure.phabricator.com/D2531