Add it to the autoloader for the tests, and remove the unneeded use
statements which cause test failures.
Change-Id: I7092525eae440c6969fc84e8979572957733cf03
This MessageLocalizer may be used in tests. By default, it sets the
language for all messages to 'qqx', to make the tests independent of the
$wgLanguageCode of the wiki the tests are running in.
Change-Id: I7412ec49b6c0fab8146e09bb8aa599b35d88fc97