Split make room for outgoing call into a separate method for emergency

1) Reading makeRoomForOutgoingCall is difficult, since it handles many
branching cases. Instead, split into makeRoomForOutgoingCall and
makeRoomForOutgoingEmergencyCall to two separate methods in order
to improve readability.

2) For new outgoing emergency calls, fix an issue where we would
not reject incoming calls if there was already an active call.
Instead, always reject any ringing/simulated_ringing calls if
a new outgoing emergency call is placed.

Bug: 157763962
Test: atest CtsTelecomTestCases TelecomUnitTests
Change-Id: Ieb558894ff8ca5b36003a45abfd2bb9542ea21e0