Big cleanup of how tests run

By default, all tests run at en.wikipedia.beta.wmflabs.org and
test2.wikipedia.org.
No tests run at en.wikipedia.org any more.
Removed @phantomjs-bug since we do not use it at the moment.
Sorted Cucumber tags alphabetically.

Change-Id: I6a7cb4cbf824cd7a89b6f441d8310dc24a27e6dc