JALDefaultUserDataDictionarySpecTests: consolidate existing tests and documentation

After so much back and forth with th actual class, the test
documentation had become stale, so I went over it again, making sure
all tests fully documented according to current requirements. That
hilighted a few small anomolies in the tests, which were then also
updated appropriately.

So there are still 2 tests missing (getting class names with
valid/invalid) inputs, but what's there is no 100% complete and
consistent with no loose ends.