The runs are now called as primary (no suffix) and secondary. This is in
preparation to adding secondary builds on CI, which will run tests on the latest
released stable V8 binary (aka as ref builds).

R=machenbach@chromium.org

Bug: chromium:783763
Change-Id: Ie6560012887bd5bb0d948bc8d34a9256d922137c
Reviewed-on: https://chromium-review.googlesource.com/781941Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49560}