Fix memory leak in ByteTracker

[sr99622]

Problem with ByteTracker during long running process. Virtual memory is consumed in same manner as memory leak. This is due to the self.removed_stracks list member variable growing without bound. The issue may be fixed by removing stale tracks from the self.removed_stracks list. A limit is placed such that tracks older than 10 * self.max_time_lost are removed from the self.removed_stracks list. This change had no discernible effect on the algorithm.

[Vladimir-125]

Thanks!