The Java API's specify sleep and wait values as 64-bit Java longs, which
leads one to expect that we mean that. It's not so, as the internal
routines responsible for implementing the waits and sleeps, mainly
monitorWait(), take C int's, and values greater than Integer.MAX_INT are
limited to Integer.MAX_INT. This means we can't do sleeps longer than
Integer.MAX_INT millis, which is something like a month. People have
already wanted to do so, say for a time bomb on a server.

I'd thought that this would be a problem to fix because I'd thought that
monitorWait was exported via the JIT API, but that turns out to be not
so. Instead, it's just a pain having to deal with all these 64-bit
thingies.