Add unit test for no NetOutput

tests/ut/ge/graph/load/davinci_model_unittest.cc

@@ -345,7 +345,7 @@ TEST_F(UtestDavinciModel, Init_variable_op) {
 
   EXPECT_EQ(model.InitNodes(graph), SUCCESS);
 
-  EXPECT_EQ(model.ReturnNoOutput(1), PARAM_INVALID);
+  EXPECT_EQ(model.ReturnNoOutput(1), SUCCESS);
   EXPECT_EQ(model.SyncVarData(), SUCCESS);
 
   OutputData output_data;