The old method skipped tests by adding a hook to
clojure.test/test-var, the problem being that :each fixtures
associated with the test have already run at that point, which is
unideal.
This change skips test by removing their :test metadata before running
the tests at all, which causes clojure.test to not see it as a test.
We use ns-interns to enumerate the vars, the same way clojure.test
does.
