Reland "Add win-msvc-{dbg,rel} as 5% experiments in the CQ."

This re-lands #516566 to add win-msvc-{dbg,rel} as 5% experiments in
the CQ, with the typo fixed :).

Tbr: iannucci@chromium.org
Bug: 751220, 777642
Change-Id: I694fa957e8e2fe518419c5098891047fc3323afd
Reviewed-on: https://chromium-review.googlesource.com/770523
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516586}
1 file changed