Real.maxFinite and friends

[Matthew Fluet]

> there are future uses.  This means I could imagine the following program:
> 
> val r = Real.minNormalPos / 3.0
> val b1 = Real.isNormal r
> val b2 = Real.>(r, 0.0)
> val b3 = Real.<(r, Real.minNormalPos)
> val b = b1 andalso b2 andalso b3
> val _ = print ((Bool.toString b) ^ "\n")
> 
> would print true.  It currently prints true if you move Real.isNormal to
> be the last test.

Whoops, this always prints false;  I thought isNormal would return true if
the value were 0.0, but normals are non-zero.  But, I think you see what
I'm getting at.

As it stands, the fact that b2 and b3 are both true is somewhat strange.