Explicitly set DateFormat.is24Hour value needed by tests

Some tests fail under CTS if the device is set to use the 24 hour clock.
The tests that depend on the value of the setting are now being explicit.

Bug: 20899571
Bug: 20937589
Bug: 20939139
Bug: 20378566
Bug: 21585934
Bug: https://code.google.com/p/android/issues/detail?id=162384
(cherry-picked from commit 38a0b85afd4231f46fac59e59ee38729bd5154c4)

Change-Id: Iac9eb15e8bf767bb5f3e96f9ba0486a995eef034
4 files changed