This should help prevent regressions

This neither adds nor deletes any test case.

These corpora came about in stupid ways, but they're the work of
weeks, so I might as well put them someplace.

In most cases I started with something Tor had produced.  For
descriptors, I included things Tor had produced long ago, as well as
an artificial "maximal" descriptor I cooked up myself.  Then I
tossed the sets back and forth between afl and libfuzzer a few
times, then minimized with afl-cmin.

If you have a decent computer, you should be able to replace this
work much faster; I'm on a 4-core 2.33GHz Q8200 at the moment.