Glue test processors and predictions

[shoarora]

Adress #3176

• Adds a function to load the test dataset for each GLUE task processor.
• Update run_glue.py example script to add a --do_test flag for producing test set predictions in a .tsv file, submittable to the GLUE scoreboard.
• Adds a couple extra feature flags to run_glue.py that don't need to stay.

[shoarora]

hm my local isort passes even on a clean env

(transformers) shoarora@sho-5:~/transformers ‹glue-test-processors›
$ make style
black --line-length 119 --target-version py35 examples templates tests src utils
All done! ✨ 🍰 ✨
243 files left unchanged.
isort --recursive examples templates tests src utils
(transformers) shoarora@sho-5:~/transformers ‹glue-test-processors›
$ which isort
/home/shoarora/miniconda3/envs/transformers/bin/isort

Ultimately, I ran it in the circleci/python:3.6 docker image to get the correct formatting. This disagrees with what happens when I style locally in a clean env.

[julien-c]

Hi @shoarora, this is a good addition but in the meantime we updated the run_glue script (and associated utilities) quite a bit in #3800.

Would you like to take a stab at updating this (probably opening a new PR)? The Trainer's predict method accepts non-labelled datasets now so it should be pretty straightforward to hook it. Let us know, otherwise we'll do it down the line.

[ZhaofengWu]

Would love to see this updated and merged :)

[julien-c]

@ZhaofengWu You can check out #4463 which we are going to take a look at soon

[ZhaofengWu]

Thanks!

[julien-c]

Closed by #4463