1.5.1 PlaybackTimeRule currentTime can get out of sync with the currentTime resulting in no seeking and duplicate requests

Created by: JibberJim

Another seeking bug in 1.5.1, certain scenarios the currentTime in the playbackTimeRule can get out of sync with the actual time the media player is trying to play, this results in the wrong fragment being requested, which can either duplicate requests - which will then break ABR (since the duplicated request will come from the cache with super fast throughput) and can also cause audio glitching (if the fragment that is playing out is re-downloaded).

The playback controller time will also become NaN after complete playback, which will also result in valid requests not being scheduled, and the video just permanently buffering. Most of these Seeking bugs simply result in a permanently spinning buffer but are not 100% reproducible, but are very easily reproducible.