Remove ash_unittests to see if it's affecting bot stability

Remove ash_unittests to see if it's affecting bot stability

Bot has been completely failing intermittently. ash_unittests
is the Win8-specific part that runs here, so temporarily remove
it to see if it's related to the back-and-forth to Metro
switches.

BUG=340422
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284820

[sky, 2014-07-22 19:12:33]

LGTM

[scottmg, 2014-07-22 19:41:58]

The CQ bit was checked by scottmg@chromium.org

[commit-bot: I haz the power, 2014-07-22 19:43:59]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/scottmg@chromium.org/411673002/1

[commit-bot: I haz the power, 2014-07-22 22:40:57]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-07-23 00:14:28]

Change committed as 284820

[scottmg, 2014-07-23 18:00:09]

A revert of this CL has been created in
https://codereview.chromium.org/414783002/ by scottmg@chromium.org.

The reason for reverting is: Was not the cause of flakiness..