Have seq2seq just use gather (#27025)
* Have seq2seq just use gather
* Change
* Reset after
* Make slow
* Apply suggestions from code review
Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>
* Clean
* Simplify and just use gather
* Update tests/trainer/test_trainer_seq2seq.py
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
* gather always for seq2seq
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Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
