testing in production

Stream: general

[Johan Commelin]

As you may have noticed, I merged a testing PR into mathlib master by accident. Sorry! I have already reverted the commit.

But things got worse: I disabled a bunch of CI workflows on leanprover-community/mathlib. Again, I thought I was working on my own testing copy :face_palm: I'm really sorry if this canceled CI on your branch.

By now, everything should be back in good state.