Merge kernel closure conversion into the Dart SDK

pkg/kernel/testcases/closures/field.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.md file.
+
+var x = () => "x";
+
+class C<T> {
+  var v = (x) => x is T;
+
+  final y = () => "y";
+
+  static final z = () => "z";
+}
+
+main() {
+  if (!new C<String>().v("")) throw "C<String>.v false on String";
+  if (new C<String>().v(0)) throw "C<String>.v true on int";
+  if (new C<String>().v(null)) throw "C<String>.v true on null";
+  if (new C<int>().v("")) throw "C<int>.v true on String";
+  if (!new C<int>().v(0)) throw "C<int>.v false on int";
+  if (new C<int>().v(null)) throw "C<int>.v true on null";
+  if ("x" != x()) throw "x";
+  if ("y" != new C<String>().y()) throw "y";
+  if ("z" != C.z()) throw "z";
+}