Fix issue 4361 by checking in the resolver if the getter/setter exists.

tests/language/setter_no_getter_test.dart

Index: tests/language/setter_no_getter_test.dart
===================================================================
--- tests/language/setter_no_getter_test.dart	(revision 11766)
+++ tests/language/setter_no_getter_test.dart	(working copy)
@@ -2,23 +2,11 @@
 // 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.
 
-var topLevelClosure;
-
 /*    /// 01: compile-time error
-get topLevel => topLevelClosure;
+get topLevel => 42;
 */   /// 01: continued
 set topLevel(var value) { }
 
-initialize() {
-  print("initializing");
-  topLevelClosure = tlc(x) => x * 2;
-}
-
 main() {
-  initialize();
-  var x = topLevelClosure(2);
-  Expect.equals(4, x);
-
-  x = topLevel(3);
-  Expect.equals(6, x);
-}
+  Expect.equals(42, topLevel++); /// 01: continued
+}