Reset DateFormat.is24Hour after each test

Bug: 20899571
Bug: 20937589
Bug: 20939139
Bug: 20378566
Bug: 21585934
Bug: https://code.google.com/p/android/issues/detail?id=162384
Change-Id: I3edb30eb5228e5d36b50867675fea9a8cdb1b2d2
1 file changed