[FIX] fix run_generation.py to work with batch_size > 1
I expended the `top_k_top_p_filtering` function, and by that the`run_generation.py` script to work with num_samples > 1.

This can be expended by scattering the sorted tensors.
First pull request in this repository, so let me know if I need to do anything else :)

Cheers, Matan.
@thomwolf
I created this PR to deal with the `top p` generations.
Should I have opened an issue first to check if it is needed?
Should I deal with the conflicts?

Cheers.<|||||>Hi @mataney, thanks.

This was rebased, fixed by https://github.com/huggingface/transformers/commit/f96ce1c24151349251880c95e9a9fb144b62367c, and merged to master by 2a5663c28043dc6d2746e69f0fb89e0d5872c63d.

Check that everything looks good on your side if you can.