HFP: Send caller ID in +CLIP command (2/4)

* Modify HeadsetCallState and native interface so that
  phoneStateChanged() method can provide caller display name
* Add unit tests to check if the name got from BluetoothHeadset
  successfully delivered to native.

Bug: 111378831
Test: runtest bluetooth, runtest -x BluetoothPhoneServiceTest.java
Change-Id: Ieb09c1146a16b11eca451138fa173a4ca815ffb6