Changing loop count ignored when playing near end of media

Changing loop count of QMediaPlayer has no effect if done after demuxing has finished.

Steps to reproduce:

1. Open MediaPlayer demo, and open a media file
2. Play media near the end of the file (within ~4 sec of the end)
3. Set infinite looping (if already set, reset instead)

Expected:

Media stops/loops according to the newly requested loop count

Actual:

Media stops/loops according to the previous loop count.

This is because the demuxing is finished at this point. We should see if there's a good way of handling this.

Workaround:

Set loop count before playing the media.