Delays scheduled to wake after ~49 days of uptime may fail to fire

[blairmcg]

The millisecond clock value primitive answers a 32-bit value that wraps around after approximately 49 days. Delays that are scheduled before the clock wraps for times after the clock wraps will probably not fire because the clock will never reach their resumption time.
Rather than making the Delay class tolerant of the clock wrapping, the best fix is for the VM to use some kind of 64-bit millisecond clock value. Although this will still wrap, after more than 500 million years, who will care.