changed.

However,

The tests for stats.distributions are real random tests. And we introduced the seeds to avoid random failures which are supposed to show up with some small probability. 
Reproducing test failures wasn't an argument for random seeds at the time.

In the cases here the test result is deterministic (always pass), and something very weird has to go on on a platform to cause an error. (For example introducing nan's somewhere.)  And in this case, I think, it would still be useful to test "permutations" (and not just the function of the test.)

But that's not the purpose of the test here.