Make initializing formals visible in the initializer list

tests/language/initializing_formal_type_test.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // DartOptions=--initializing-formal-access
+// VMOptions=--initializing-formal-access
 
 import "package:expect/expect.dart";
 
 class A {
   int x;
   String y;
   A(this.x) : y = x { y = x; }
 }
 
 main() {
   A a = new A(null);
   Expect.equals(a.x, null);
   Expect.equals(a.y, null);
 }