mwext-TimedMediaHandler-testextensions-master is now voting

We have set a bunch of workaround to get failling tests to be ignored by
phpunit. Bug have been filled as blockers of bug 61875.

Since tests are now passing, make them vote!

Bug: 61875
Change-Id: I6e1b10d7cfce84a844e4208ccbf9a11e4303e7eb