Additional Monitors test cases

I have put up a patch for you to look at.
  https://savannah.gnu.org/patch/index.php?func=detailitem&item_id=3006

The patch just adds some more tests for monitors.  I have verified that
all the tests pass when run under VS.  I wrote the tests originally to
demonstrate a bug in Monitor.Wait().  They failed miserably at that
task, but it turns out they do show up a bug in Interrupting
System.Threading.Thread.Sleep(), so they ended up being good for
something.  If you agree either apply it yourself, or let me know and I
will apply it.

The bug I was trying to demonstrate now think is dammed near impossible
to demonstrate with a test.  In the current CVS,
  pnet/support/wait_mutex.c, line 587,
ILWaitMonitorWait calls ILWaitOne.  ILWaitOne will return
IL_WAIT_INTERRUPTED if there is an interrupt pending.  At least I think
so - I can't see anything that would prevent it from doing that.  I am
fairly sure it should not be possible to interrupt or abort that wait. 
The MS doco is vague on the issue, but the Java docs for java the
equivalent aren't:
http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Object.html#wait(long)

The books I have say the C# implementation is meant to mimic the Java
one.