rebaseline-o-matic shouldn't hang if git cl does.

Sometimes git cl upload hangs. Obviously that should be fixed,
but in the meantime, rebaseline-o-matic should recover.
If git cl doesn't give any output for 5 minutes, give up and
start over.

Also, this fixes the bug where we wouldn't log git cl output
to the log server.

Fixed a bug where MockExecutive didn't record executive.call
calls.

BUG=347628

Review URL: https://codereview.chromium.org/291543004

git-svn-id: svn://svn.chromium.org/blink/trunk@174244 bbb929c8-8fbe-4397-9dbb-9b2b20218538