Add build flag to control runtime annotator checks. This restores the prior path where angle_enable_trace would let ANGLE write a debug.txt file without needing environment variables or run-time annotator attachments. Bug: b/170249632 Change-Id: I28693f038572638eb6531c5bb8e42d6cc7a65451 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2523912 Reviewed-by: Ian Elliott <ianelliott@google.com> Commit-Queue: Ian Elliott <ianelliott@google.com>