[Bart] Refactor - fix issues, consistency with the library, naming (#8900)

* remove make on the fly linear embedding

* start refactor

* big first refactor

* save intermediate

* save intermediat

* correct mask issue

* save tests

* refactor padding masks

* make all tests pass

* further refactor

* make pegasus test pass

* fix bool if

* fix leftover tests

* continue

* bart renaming

* delete torchscript test hack

* fix imports in tests

* correct shift

* fix docs and repo cons

* re-add fix for FSTM

* typo in test

* fix typo

* fix another typo

* continue

* hot fix 2 for tf

* small fixes

* refactor types linting

* continue

* finish refactor

* fix import in tests

* better bart names

* further refactor and add test

* delete hack

* apply sylvains and lysandres commens

* small perf improv

* further perf improv

* improv perf

* fix typo

* make style

* small perf improv

tests/test_modeling_rag.py

@@ -37,7 +37,7 @@ from transformers.testing_utils import (
     torch_device,
 )
 
-from .test_modeling_bart import ModelTester as BartModelTester
+from .test_modeling_bart import BartModelTester
 from .test_modeling_dpr import DPRModelTester
 from .test_modeling_t5 import T5ModelTester