Make concat test rely on DC normalization

• Make concat test rely on DC normalization.

juno_samples/concat/src/concat.jn

@@ -28,5 +28,5 @@ fn concat_entry(a : i32) -> i32 {
   arr2[4] = a;
   arr2[5] = a;
   let arr3 = concat::<i32, 3, 6>(arr1, arr2);
-  return sum::<i32, 3 + 6>(arr3);
+  return sum::<i32, 9>(arr3);
 }