Time bug work around

[Stephen Weeks]

> Looking through the code, the only things that could raise the Time
> exception were Time.- and some of the Time.from* functions.  I still think
> it has to be coming from a Time.from* call within the MLton.Rusage.rusage
> call, because if it were coming from showTime, you would have seen "Binfo
> for ..." before the unhandled exception was raised.

I agree.  The only suggestion that I can make is to put a handler around the
Rusage.get and run the grinder some more.