Add randomized tests

[stylewarning]

It's possible to do more comprehensive testing with randomized tests. Something like

(let ((r (random most-positive-double-float)))
  (= r (parse-float:parse-float (prin1-to-string r) :type 'double-float
                                                    :exponent-character #\d)))

[soemraws]

Nice idea.

Do you now if random states are the same across all platforms? I would hate it if test 213 fails on one computer and I cannot reproduce it on mine.

[stylewarning]

Random states are definitely not portable, unfortunately.

For single floats, we may opt to just test them all. Why not?

[adlai]

The random-state should only determine the order in which tests are performed. Some predicates could eliminate most candidates, although any failure should be reported in a way that enables its isolation, so that volunteers without the resources to run more than the minimal test cases should still be able to keep regressions out of their proposed fixes.