MessageDifferencer ignoreFields doesn't work for RepeatedFields.

```message A {
    message B {
        message C {
            optional string details = 1;
            optional string time = 2;
        }
        repeated C c = 1;
    }
    repeated B b = 1;
}```

If message is of the above form and if we add details to ignoreField MessageDifferencer.compare doesn't work if number of RepeatedFields is different.