wip:X16 rng chisq test
The code calculates chi-squared to compare two distributions and the probability that the sampled data comes from the same distribution.
The code is not ready for merge with master, and I do not think it is absolutely essential for it to be part of master. If it is to be included in master, it should be improved to include more code-sharing with random-numbers/test.lisp
It is the editor-in-chief's choice whether code like this should be part of GSLL.