[tests] add "return" for dummy test platform API (#6000)
[tests] add "return" for dummy test platform API (#6000)


abtink/openthread,openthread/openthread,openthread/openthread,srickardti/openthread,abtink/openthread,abtink/openthread,jwhui/openthread,srickardti/openthread,abtink/openthread,jwhui/openthread,srickardti/openthread,srickardti/openthread,openthread/openthread,jwhui/openthread,openthread/openthread,jwhui/openthread