[perf] Fix bug with duplicate commit timestamps.
[perf] Fix bug with duplicate commit timestamps.

Bug: skia:10698
Change-Id: I35f8d6501d24152bc8e4c6729ad09a5aeab0c31b
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/315317
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>
Commit-Queue: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot