Update to PHPUnit 4.4.2

Currently we are stuck on an old branch of PHPUnit (4.1.x) because we have some tests that are using methods that are deprecated in PHPUnit 4.2. Once these deprecated methods are removed in #2331685: PHPUnit deprecated assertTag(), assertNotTag() and assertSelectEquals() we can update PHPUnit to the latest 4.4.2.

This is postponed on #2331685: PHPUnit deprecated assertTag(), assertNotTag() and assertSelectEquals().