[autotest] Bump NightlyRegression to |num: 2|.

NightlyRegression, which runs the regression suite, recently had a test
with the |webcam| dependency added, and thus now needs 2 machines.

TEST=suite_scheduler --sanity
BUG=None

Change-Id: I874e6f9cfc432ba0cb8cd5a1a7f9442183a8537f
Reviewed-on: https://gerrit.chromium.org/gerrit/40464
Tested-by: Alex Miller <milleral@chromium.org>
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Queue: Alex Miller <milleral@chromium.org>
1 file changed