Fix getField optimization when the selector is an operator.

tests/lib/mirrors/hot_get_field_test.dart

 // Copyright (c) 2014, 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.
 
 library test.hot_get_field;
 
 import 'dart:mirrors';
 import 'package:expect/expect.dart';
 
 class C {
   var field;
   var _field;
+  operator +(other) => field + other;
 }
 
 const int optimizationThreshold = 20;
 
 testPublic() {
   var c = new C();
   var im = reflect(c);
 
   for (int i = 0; i < (2 * optimizationThreshold); i++) {
     c.field = i;
@@ skipping 14 matching lines @@
 testPrivateWrongLibrary() {
   var c = new C();
   var im = reflect(c);
   var selector = MirrorSystem.getSymbol('_field', reflectClass(Mirror).owner);
 
   for (int i = 0; i < (2 * optimizationThreshold); i++) {
     Expect.throws(() => im.getField(selector), (e) => e is NoSuchMethodError);
   }
 }
 
+testOperator() {
+  var plus = const Symbol("+");
+  var c = new C();
+  var im = reflect(c);
+
+  for (int i = 0; i < (2 * optimizationThreshold); i++) {
+    c.field = i;
+    var closurizedPlus = im.getField(plus).reflectee;
+    Expect.isTrue(closurizedPlus is Function);
+    Expect.equals(2 * i, closurizedPlus(i));
+  }
+}
+
 main() {
   testPublic();
   testPrivate();
   testPrivateWrongLibrary();
+  testOperator();
 }