This change is to facilitate the annotation protocol -> luciexe protocol
migration in the future. The failure response structure will be changed
after the migration. Therefore, we only need to change the
implementation detail of ResultReasonRE at that time.

R=iannucci

Change-Id: If5e0005dddcaf6ccdfbcb047e3855763cf4eadc5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2146066
Auto-Submit: Yiwei Zhang <yiwzhang@google.com>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>