Stop inheriting tests! (#42192)

* Stop inheriting tests!

* Just use a del instead

* fixup

Author: Rocketknight1

tests/models/cohere2/test_modeling_cohere2.py

@@ -269,3 +269,6 @@ def test_generation_beyond_sliding_window(self, attn_implementation: str):
         output_text = tokenizer.batch_decode(out)
 
         self.assertEqual(output_text, EXPECTED_COMPLETIONS)
+
+
+del CohereModelTest, CohereModelTester  # So the parent tests don't run in this file too

tests/models/granitemoehybrid/test_modeling_granitemoehybrid.py

@@ -178,3 +178,6 @@ def test_model_generation(self):
         text = tokenizer.decode(generated_ids[0], skip_special_tokens=True)
 
         self.assertEqual(EXPECTED_TEXT_COMPLETION, text)
+
+
+del BambaModelTest, BambaModelTester  # So the parent tests don't run in this file too