GitLab

* 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>