A teacher would refer all of these children for intelligence testing except for a child who:

The answer to this question is children who receives moderate to good grades in all school subjects.

The main purpose of teacher advocating the intellegence testing is to make sure that the children has the capability that suitable for his/her current class.

So, the appropriate type of chilredn to be subjected to such tests would be the one that seem too smart or too incapable in following the classes.