* [tests] Switch to OverfitTeacher for some model tests.

* Black.

* Improve on distributed training.

* Screw this test.

* Try lowering parallelism.

* Looser requirements on test_distributed.

* Speed up drqa test.

* Faster dynamic batch test.

* Speed up deepcopies of opts.

* Fewer deepcopies.

* Verify data relaxation.

* Robust

* Lint.

* make hred more reliable

* try again.

* Speed up beam block test.

* Speed up more generation tests.

* Bring back one more retry.

* Whopos.

* Always kill process group i  guess.

* We can save the company some $

* Another test combo failure.

* Lint.

* Use constants.