[autotest] Add a tick stat to the scheduler.

BUG=chromium-os:36682
TEST=ran scheduler, saw stat on chromeos-stats

Change-Id: Ic084d23be424e3d8e7e4de32c1d6ffe1e3342728
Reviewed-on: https://gerrit.chromium.org/gerrit/45139
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Queue: Alex Miller <milleral@chromium.org>
Tested-by: Alex Miller <milleral@chromium.org>
2 files changed