Consider computing test data during tests.

[lang-m]

We have a script to compute the test data used and commited to the repository. It runs in a few seconds. We should consider recreating the data for the tests because we do not detect changes in the code that creates the data. Therefore, we initially missed the recent change in the HysteresisDriver (renaming the hysteresis field) that should have broken the tests in micromagnetictests.