Fixed an incorrect test case where MediaPlayer.start() was called right after MediaPlayer.stop() was called.

I also changed the test case so that it becomes more interesting:
1) video plays on surface A.
2) switch to use surface B.
3) switch to use a null surface.
4) switch back to use surface A.

o related-to-bug: 6158159

Change-Id: I2f5f9ad4077017c37ab4912c9cea48c3e7020621
2 files changed