This moves all browser tests from MobileFrontend to the Minerva repo
in preparation for separating the two.
Note, this means browser tests will exist in both repositories for a
period of time. This is important and necessary to ensure we do not
break anything.
See:
https://lists.wikimedia.org/pipermail/mobile-l/2017-July/010536.html
Bug: T168758
Change-Id: I84ae3ea14191f672cabcd52020e80b0a40a72ce1
