Fix Regent Test Timeout

This branch fixes a bug in the Regent testing script that would only detect timeouts in the case where there were still running threads. If the process deadlocked and all the threads went to sleep before the budget was exceeded then the test script would hang waiting forever. This fix works by applying a true wall-clock time to the process regardless of whether the threads are running or not. This was issue was observed in practice when @rhoque was degugging a branch and hangs were being encountered on a single node before the budget had been exceeded.

Note: I suspect this issue has survived this long, because most hangs occurred on multi-node machines and the GASNet progress through would be actively polling and always trip the resource budget. However, that doesn't apply to single node runs without GASNet.