The QC driver was repeating HIGH priority messages about map flags.

Bug: angleproject:4943
Change-Id: I927c38249f840544a7c1f5e595fa34e706e401bd
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2352472Reviewed-by: Cody Northrop <cnorthrop@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>