Test: Following scenarios for VoLTE and CS call and
verified the cause sent in PreciseCallState.
1) Conference call merge
2) Conference call, one remote party ends the call
3) Conference call, all remote parties end the call
4) Conference call, hangup locally
5) Normal call and hangup locally
6) Normal call and remote party ends the call
Bug: 38225047
Change-Id: I36edb0cbff4b130b0942a46dc6c15a7d842789c2