Fix set test, number of arguments to helper function changed.

tests/corelib/set_test.dart

Index: tests/corelib/set_test.dart
diff --git a/tests/corelib/set_test.dart b/tests/corelib/set_test.dart
index f1a01fd548e3465a3d8de6a2ab538c832bbe7eb7..32ec5206c2430db4b24acc07c88d47e521d54092 100644
--- a/tests/corelib/set_test.dart
+++ b/tests/corelib/set_test.dart
@@ -243,7 +243,7 @@ void testTypeAnnotations(Set<int> set) {
   testLength(1, set);
 }
 
-void testRetainWhere(Set create([equals, hashCode, validKey])) {
+void testRetainWhere(Set create([equals, hashCode, validKey, compare])) {
   // The retainWhere method must not collapse the argument Iterable
   // in a way that doesn't match the equality of the set.
   // It must not throw away equal elements that are different in the