[LongT5] disable model parallel test (#17702)

tests/models/longt5/test_modeling_longt5.py

@@ -505,11 +505,10 @@ class LongT5ModelTest(ModelTesterMixin, GenerationTesterMixin, unittest.TestCase
     all_model_classes = (LongT5Model, LongT5ForConditionalGeneration) if is_torch_available() else ()
     all_generative_model_classes = (LongT5ForConditionalGeneration,) if is_torch_available() else ()
     fx_compatible = False
-    all_parallelizable_model_classes = (LongT5Model, LongT5ForConditionalGeneration) if is_torch_available() else ()
     test_pruning = False
     test_torchscript = True
     test_resize_embeddings = True
-    test_model_parallel = True
+    test_model_parallel = False
     is_encoder_decoder = True
 
     def setUp(self):
@@ -1013,8 +1012,7 @@ class LongT5EncoderOnlyModelTest(ModelTesterMixin, unittest.TestCase):
     test_pruning = False
     test_torchscript = True
     test_resize_embeddings = False
-    test_model_parallel = True
-    all_parallelizable_model_classes = (LongT5EncoderModel,) if is_torch_available() else ()
+    test_model_parallel = False
 
     def setUp(self):
         self.model_tester = LongT5EncoderOnlyModelTester(self)