Move debug-tests out of MediaWikiPHPUnitCommand

This also slightly refactors MediaWikiPHPUnitTestListener
so we can pass it into phpunit directly using the
--printer option

Change-Id: I6a19e3902130eeba6a0941f24a4f440b712058e5
Remove MediaWikiPHPUnitCommand

All functionality has been moved to other places

Change-Id: I6b6b0ef846bc63108c4dff9e17098432fd9d1697