[[ Bug 22650 ]] Fix crash on iOS player

This patch fixes a crash/freeze when repeatedly setting the same filename in an iOS player.

The patch ensures that two AVPlayerItems are checked for equality correctly, so the rest of the setCurrentItem method is not executed.

However, when setting repeatedly different filenames, the crash/freeze is still present. It happens completely randomly, it can happen at the second attempt to change the filename, or even at the 20th one. It looks like something in the setCurrentItem method is the culprit.

This, setting it to WIP for now.