[tests] remove tests from libraries with deprecated support (flax, tensorflow_text, ...) (#39051)

* rm tf/flax tests

* more flax deletions

* revert fixture change

* reverted test that should not be deleted; rm tf/flax test

* revert

* fix a few add-model-like tests

* fix add-model-like checkpoint source

* a few more

* test_get_model_files_only_pt fix

* fix test_retrieve_info_for_model_with_xxx

* fix test_retrieve_model_classes

* relative paths are the devil

* add todo

tests/test_modeling_common.py

@@ -2453,10 +2453,6 @@ class ModelTesterMixin:
 
         return new_tf_outputs, new_pt_outputs
 
-    def assert_almost_equals(self, a: np.ndarray, b: np.ndarray, tol: float):
-        diff = np.abs(a - b).max()
-        self.assertLessEqual(diff, tol, f"Difference between torch and flax is {diff} (>= {tol}).")
-
     def test_inputs_embeds(self):
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()