dart2js: Emit static const fields if accessible by reflections.

tests/lib/mirrors/static_const_field_test.dart

 // Copyright (c) 2013, 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.
 
-// Test reflection of private functions in core classes.
+// Test that static const fields are accessible by reflection.
+// Regression test for http://dartbug.com/23811.
 
+@MirrorsUsed(targets: const [A])
+import "dart:mirrors";
 import "package:expect/expect.dart";
-import "dart:mirrors";
+
+class A {
+  static const ONE = 1;
+}
 
 main() {
-  var s = "string";
-  var im = reflect(s);
-  Expect.throws(() => im.invoke(const Symbol("_setAt"), [0, 65]), (e) => e is NoSuchMethodError);
+  Expect.equals(1, reflectClass(A).getField(#ONE).reflectee);
 }
-