Add PRESUBMIT check to ensure these config files stay correct. Bug: 973721 Change-Id: Ife5884d39ca22c55fdc58b65220ed0c34c85fb6a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1743048 Commit-Queue: Robbie Iannucci <iannucci@chromium.org> Reviewed-by:Jamie Madill <jmadill@chromium.org>