Run latency_unittests on mac and cast bots.

I don't know what ui/latency does, but the test is small and builds
and runs fine, so just run it.

Also remove now-empty and currently-unused non_mac_chromium_gtests.

Bug: 843511
Change-Id: I71abcab45133bb235f268f34e4df6097758867d4
Reviewed-on: https://chromium-review.googlesource.com/1129680
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573544}
6 files changed