Planning to enable Mac a11y tests on 1.9.2 (mozilla-central + tracemonkey)

[Ben Hearsum]

Hi Everyone,

On Monday, May 11th we're planning on enabling Mac accessibility tests
for 1.9.2. Specifically, this means a mozconfig change for the unittest
builds on mozilla-central and tracemonkey plus the actual running of the
tests.

To the best of my knowledge all of the tests are passing, so this change
should go unnoticed.

If there's any reason we shouldn't proceed with this please let me know.

For anyone interested, this work is being tracked in
https://bugzilla.mozilla.org/show_bug.cgi?id=482598.

- Ben