Flax T5 (#12150)

* copy pytorch-t5

* init

* boom boom

* forward pass same

* make generation work

* add more tests

* make test work

* finish normal tests

* make fix-copies

* finish quality

* correct slow example

* correct slow test

* version table

* upload models

* Update tests/test_modeling_flax_t5.py

* correct incorrectly deleted line

Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
Co-authored-by: Patrick von Platen <patrick@huggingface.co>

tests/test_modeling_flax_bart.py

@@ -72,7 +72,7 @@ def prepare_bart_inputs_dict(
     }
 
 
-class FlaxBartModelTester(unittest.TestCase):
+class FlaxBartModelTester:
     def __init__(
         self,
         parent,