Merge the Isilon ATF code

This is a placeholder merge request to go over all of the items to ensure that I understand everything, some of the items from Isilon can be dropped as I dropped them from the atf branch (diff reduction), and make sure that any valid fixes from NetBSD can be pushed back.
This should be #define'd to isinf as FreeBSD automatically muxes according to the type:

<pre>
% grep -r isinf /usr/include/math.h 
#define	isinf(x) __fp_type_select(x, __isinff, __isinf, __isinfl)
</pre>