Check that critical processes are running in VMTest.

This is needed for ensuring that the pre-cq catches bad
patches that prevent necessary processes from starting up.

BUG=chromium:419423
TEST=Run it.

Change-Id: I4214530ff7d212454d5d0eac765709c50345a5a3
Reviewed-on: https://chromium-review.googlesource.com/220841
Reviewed-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: Gaurav Shah <gauravsh@chromium.org>
Commit-Queue: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
5 files changed