Regenerate test_data files using filter-cascade 0.4.1

Running `python make-sample-data.py` with the latest version of filter-cascade (0.4.1) does not reproduce the files in the `test_data` directory. The files currently in `test_data` are larger than expected and seem to have been generated by a filter-cascade with a version number < 0.3.0. Let's regenerate them.