Clean up test runner TODOs. Bug: angleproject:3162 Change-Id: Ie0a137341c7a27a1981c9a39a8e07e437589520a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2495280 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>