[ci] fix 3 remaining slow GPU failures (#4584)

tests/test_modeling_tf_electra.py

@@ -222,6 +222,6 @@ class TFElectraModelTest(TFModelTesterMixin, unittest.TestCase):
     @slow
     def test_model_from_pretrained(self):
         # for model_name in list(TF_ELECTRA_PRETRAINED_MODEL_ARCHIVE_MAP.keys())[:1]:
-        for model_name in ["electra-small-discriminator"]:
+        for model_name in ["google/electra-small-discriminator"]:
             model = TFElectraModel.from_pretrained(model_name)
             self.assertIsNotNone(model)