They're  enabled via the chromium_code config already these days.
No intended behavior change.

Bug: chromium:926235,chromium:428099

Change-Id: I6927d6e3ec85f40454da61969d7a22dfabef1bde
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1564781Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>