How to build and run tests

BUG=angleproject:1607

Change-Id: I6d5c341c32a37535d59e8dae508173b5ab6664d6
Reviewed-on: https://chromium-review.googlesource.com/419798
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>