DO NOT MERGE Add ability to simulate missed calls

After initiating a call using
adb shell am start -a android.telecom.testapps.ACTION_START_INCOMING_CALL
-d "tel:14082932268"

Hang up the call using:
adb shell am start -a android.telecom.testapps.ACTION_HANGUP_CALLS

Bug: 19803865
Change-Id: I9ba12bac1eb5db5c19d0d830fc1e1e77cb3b86cb