Fix implementation of Function.apply with optional positional arguments.

tests/corelib/apply4_test.dart

Index: tests/corelib/apply4_test.dart
diff --git a/tests/corelib/apply4_test.dart b/tests/corelib/apply4_test.dart
index f617456fe49883d52f44b5b467d206f5f25ee99f..fba4b9d48b82b5e3deeec8a03a37835899430a01 100644
--- a/tests/corelib/apply4_test.dart
+++ b/tests/corelib/apply4_test.dart
@@ -16,5 +16,5 @@ main() {
   var a = new A();
   var clos = a.foo;
   Expect.equals(Function.apply(clos, ["well"]), "well 99");
-  Expect.equals(Function.apply(clos, ["well", 0, 1, 2, 3, 4, 5, 6]), "well 5");
+  Expect.equals(Function.apply(clos, ["well", 0, 2, 4, 3, 6, 9, 10]), "well 9");
 }