[WIP] Adapt Cookie Cutter For EncoderDecoder
Author: patrickvonplaten
Pull request: yes

# What does this PR do?

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Fixes # (issue)


## Before submitting
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 albert, bert, XLM: @LysandreJik
 GPT2: @LysandreJik, @patrickvonplaten
 tokenizers: @mfuntowicz
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 nlp datasets: [different repo](https://github.com/huggingface/nlp)
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 EncoderDecoder: @patrickvonplaten
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Comments:
Cleaner version here: https://github.com/huggingface/transformers/pull/9251