unittest: multiple example forms in `deftest`
unittest: multiple example forms in `deftest`

Now `deftest` accepts any number of form to be tested, and each form
can have their own expectations.
Structure of test is changed accordingly, but test runner is not adopted
yet.

NobuoK/xyzzy,NobuoK/xyzzy,NobuoK/xyzzy,NobuoK/xyzzy,NobuoK/xyzzy