Add reference to invalid typedef so dart2js will detect it.

tests/language/named_parameters_default_eq_test.dart

Index: tests/language/named_parameters_default_eq_test.dart
diff --git a/tests/language/named_parameters_default_eq_test.dart b/tests/language/named_parameters_default_eq_test.dart
index 83abffb93dddb04c4f9f3831bf9a860238b843d7..2afc8c40377642dbba788b249bef97c8785eb110 100644
--- a/tests/language/named_parameters_default_eq_test.dart
+++ b/tests/language/named_parameters_default_eq_test.dart
@@ -32,6 +32,9 @@ class A {
 }
 
 main() {
+  // Reference the type, or dart2js won't see that the declaration is invalid
+  F1 _ = null;  /// 01: continued
+
   var a = new A();
 
   int local({x = 3, y : 5, z}) => x * y * (z ?? 2);