Remove extra call to dispatchStart().

Fixes a bug where UtteranceProgressListener.onStart is called twice
when calling TextToSpeech.synthesizeToFile().

Bug: 22262115
Test: Ran cts android.speech.tts.cts.TextToSpeechServiceTest
Change-Id: I7fa4cf824508e2880d0d74bab7a35f8678c38250
1 file changed