Add very simple test list for chromium_trybot recipe to the chromium tree

This will allow changing, adding, and removing tests without two-sided
patches.

The list format can be extended in the future, for now keeping it as simple
and static as possible.

BUG=332239
R=darin@chromium.org, iannucci@chromium.org

Review URL: https://codereview.chromium.org/166663004

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@252050 4ff67af0-8c30-449e-8e8b-ad334ec8d88c