[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/textnet/test_image_processing_textnet.py

@@ -26,7 +26,7 @@ if is_vision_available():
     from transformers import TextNetImageProcessor
 
 
-class TextNetImageProcessingTester(unittest.TestCase):
+class TextNetImageProcessingTester:
     def __init__(
         self,
         parent,