More reshuffler tests

These are some new tests for the reshuffler. Since we would like the formulas generated using a specific seed to be consistent between versions, I am adding the old reshuffler for reference and changing the polarity of the shuffle to exactly the opposite.

There is a subtle issue: even though the random generator is well-documented (an implementation of the Mersenne Twister), hashing is not, so using a string as the seed makes me uncomfortable.