Remove MediaSessionServiceImpl

Bug: 132232820
Test: atest CtsMediaTestCases:android.media.cts.MediaSessionTest;
      atest CtsMediaTestCases:android.media.cts.MediaControllerTest;
      atest CtsMediaTestCases:android.media.cts.MediaBrowserTest;
      atest CtsMediaTestCases:android.media.cts.MediaSessionManagerTest;
      atest CtsMediaTestCases:android.media.cts.MediaSession2Test;
      atest CtsMediaTestCases:android.media.cts.MediaController2Test;
      atest CtsMediaTestCases:android.media.cts.MediaSession2ServiceTest;
Change-Id: I54fcf97b73301751522748fb4fbd438691542f38
3 files changed