GitLab

This adds an is_unexpected tag, and handles multiple results (e.g.
from retries) correctly.

Bug: 931731
Bug: 1138507
Bug: angleproject:5124
Change-Id: I23054010db058eaa9d275c9b5de3052030210024
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2472338Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817288}