Revert "Add CTS coverage for new external audio route API." Revert submission 16308028-external-audio Reason for revert: Don't want to launch this in T now Reverted Changes: I6634c752a:Add CTS coverage for new external audio route API.... Ibd1c2880e:Add API for external call audio route. I3e262a913:Implement new external audio route. Change-Id: I3a3eab1151b825523499058040c14696ea2887e9