Fix various issues in video stream emulation

- Return early from EvsCamera::stopVideoStream() method when current
  video stream is already being stopped.
- Reconfigure the media codec and try again when it fails to start
  decoding a media file.
- Send the STREAM_STOPPED event after closing a video stream.
- Rewind the media extractor when it reaches the end of current source
  media file, to be able to playback repeatedly.

Bug: 335901181
Test: Run a test described in the associated bug.
Change-Id: If952a63700402885f794a7ef544f393314101606