Adding initial tests for GsmCdmaCall and GsmCdmaPhone.

Also includes:
- Changes to fix/comment out failing tests
- Some cleanup in CallManager related to deletion of PhoneBase and
PhoneProxy
- ContextFixture containing mock Context for all telephony tests
- Phone test that exercises BroadcastReceiver support in the mock
Context
- Test showing how static function can be mocked

Bug: 25691379
Change-Id: Ia38423cef3cfb86389d044cac4e601983fae1192