FBDeviceXCTestCommands notify reporter when finished
FBDeviceXCTestCommands notify reporter when finished

Summary:
if reporter is not nil setup a callback on the operation
completed that will notify reporter that the job is done.

Reviewed By: c-ryan747

Differential Revision: D5814806

fbshipit-source-id: 72b3e2273f2e763a64877cfdb22dc271cc675148

facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl