Bug in numpy_pad_and_concatenate
https://github.com/huggingface/transformers/blob/77b862847b8069d57c0849ca012f48414c427d8e/src/transformers/trainer_pt_utils.py#L71

I believe this should be 
`np.concatenate((array1, array2), axis=0)`
Indeed. Would you like to do a PR to fix this since you spotted the bug?<|||||>sure thing!<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

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