[tests] further fix Tester object has no attribute '_testMethodName' (#35781)

* bug fix

* update with more cases

* more entries

* Fix

---------

Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

tests/models/mbart/test_modeling_flax_mbart.py

@@ -74,7 +74,7 @@ def prepare_mbart_inputs_dict(
     }
 
 
-class FlaxMBartModelTester(unittest.TestCase):
+class FlaxMBartModelTester:
     def __init__(
         self,
         parent,
@@ -116,7 +116,6 @@ class FlaxMBartModelTester(unittest.TestCase):
         self.bos_token_id = bos_token_id
         self.decoder_start_token_id = decoder_start_token_id
         self.initializer_range = initializer_range
-        super().__init__()
 
     def prepare_config_and_inputs(self):
         input_ids = np.clip(ids_tensor([self.batch_size, self.seq_length - 1], self.vocab_size), 3, self.vocab_size)