Add accessibility_unittests and chromevox_tests to buildbot config.

accessibility_unittests should run everywhere except iOS. It's small and
very fast.

chromevox_tests is only for Chromium OS.

BUG=322537
NOTRY=true

Review URL: https://codereview.chromium.org/350123003

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@280566 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Drop browser_tests from the experimental MSan runner.

We now have a separate runner for that target.

BUG=178409
TBR=glider@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/343383003

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@280588 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Revert of Add accessibility_unittests and chromevox_tests to buildbot config. (https://codereview.chromium.org/350123003/)

Reason for revert:
The chromevox tests are failing (and blocking cq trybots).

Original issue's description:
> Add accessibility_unittests and chromevox_tests to buildbot config.
> 
> accessibility_unittests should run everywhere except iOS. It's small and
> very fast.
> 
> chromevox_tests is only for Chromium OS.
> 
> BUG=322537
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=280566

TBR=phajdan.jr@chromium.org,plundblad@chromium.org,dmazzoni@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=322537

Review URL: https://codereview.chromium.org/338843007

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@280590 4ff67af0-8c30-449e-8e8b-ad334ec8d88c