* Seed get_train_sampler's generator with arg seed to improve reproducibility
and make the world_size<=1 code path more similar to the others
* move test file into trainer test explicitly
* dumb typo
* make style lint happy
* per discussion, switch to data_seed
* Apply suggestions from code review
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>