[Flax] Add T5 pretraining script (#12355)
* fix_torch_device_generate_test
* remove @
* add length computatan
* finish masking
* finish
* upload
* fix some bugs
* finish
* fix dependency table
* correct tensorboard
* Apply suggestions from code review
* correct processing
* slight change init
* correct some more mistakes
* apply suggestions
* improve readme
* fix indent
* Apply suggestions from code review
Co-authored-by: SaulLu <55560583+SaulLu@users.noreply.github.com>
* correct tokenizer
* finish
* finish
* finish
* finish
Co-authored-by: Patrick von Platen <patrick@huggingface.co>
Co-authored-by: SaulLu <55560583+SaulLu@users.noreply.github.com>
