message: Update unit-test to set correctly which converter to use.
diff: @@ -531,6 +531,7 @@ class FromSessionTest(TestModels, parameterized.TestCase):
  # Convert model and ensure model is not None.
  converter = lite.TFLiteConverter.from_session(sess, [in_tensor],
  [out_tensor])
  + converter.experimental_new_converter = enable_mlir
  graphviz_dir = self.get_temp_dir()
  converter.dump_graphviz_dir = graphviz_dir
  converter.dump_graphviz_video = True
  @@ -571,6 +572,7 @@ class FromSessionTest(TestModels, parameterized.TestCase):
  # Convert model and ensure model is not None.
  converter = lite.TFLiteConverter.from_session(sess, [in_tensor],
  [out_tensor])
  + converter.experimental_new_converter = False
  log_dir = self.get_temp_dir()
  converter.conversion_summary_dir = log_dir
  tflite_model = converter.convert()
  