cps2js: Fix translation of captured 'this'.

tests/compiler/dart2js/js_backend_cps_ir_closures_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.
 // VMOptions=-DUSE_CPS_IR=true
 
 // Tests of closures.
 
 library closures_test;
 
 import 'js_backend_cps_ir.dart';
@@ skipping 99 matching lines @@
     if (P.identical(J.getInterceptor$n(i).$lt(i, v0), true)) {
       a = new V.main_closure(i);
       v1 = 1;
       i = J.getInterceptor$ns(i).$add(i, v1);
     } else {
       P.print(a.call$0());
       return null;
     }
   }
 }"""),
+
+  const TestEntry.forMethod('function(A#b)', """
+class A {
+  a() => 1;
+  b() => () => a();
+}
+main() {
+  print(new A().b()());
+}
+""",
+r"""
+function() {
+  return new V.A_b_closure(this);
+}"""),
 ];
 
 void main() {
   runTests(tests);
 }