GitLab

In order to reduce cycle time on the performance waterfall, drop the
perf test measurement period from 30s to 5s.

Bug: 897751, 848499
Change-Id: I3cd921b327044f02767bc8a43a6e99e5a8a6f48f
Reviewed-on: https://chromium-review.googlesource.com/c/1315967Reviewed-by: François Doray <fdoray@chromium.org>
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605922}