Bug 1067482 - Add support for Android instrumentation tests

I think this is all that's needed, but I haven't seen the changes take effect in my Vagrant instance.

If it's working, http://192.168.33.10/ui/#/jobs?repo=ash should have a group labeled "Inst" with both "Ba" and "Br" tests contained within it on the Android 4.0 line.
Could you update this to "I", to match:
https://hg.mozilla.org/webtools/tbpl/rev/75481643eaf0#l1.31