tests. (Buy 10, get one free!) The separate categories were
already there; they just weren't labeled.
- Use fesetround() instead of fpsetround(), since the former is
standard and implemented on all supported architectures. Add
tests for each rounding mode.
- Add additional tests for subnormals.
Some of these tests won't pass until problems in vendor sources
(gdtoa and gcc) are fixed and new versions imported, but I
want to get these changes into the tree before I accidentally
blow them away.