Fix player destruction after failed initialization

In case of a failure in IEngine_CreateAudioPlayer, the mTrackPlayer
  field of a CAudioPlayer is not initialized, which will
  cause a crash if destroy() is called on the player.

Test: run cts -m CtsMediaTestCases -t android.media.cts.AudioNativeTest#testOutputChannelMasks
Bug 34722995

Change-Id: Ia7e62779c9698581ef000c48c7ba137a5bf0c219