This initial version just includes tests for cl-loop, many of which were
adapted from Common Lisp the Language 2nd Edition. They are mostly
ordered by their appearance in the Hyperspec.

When I was just about finished I realized that I could have just used an
ert wrapper macro to avoid all of the (eval (quote ...))) business,
which would have the added bonus of easily evaluating most of the tests
lexically. Should I redo it in this way?