Merge more Kernel infrastructure from kernel_sdk SDK fork.

tests/kernel/unsorted/getters_and_setters_test.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 file.
+
+import 'expect.dart';
+
+var field;
+
+get getField {
+  print('B.getField');
+  return field;
+}
+
+set setField(value) {
+  print('B.setField');
+  field = value;
+  return null;
+}
+
+main() {
+  var result;
+
+  result = (field = 42);
+  Expect.isTrue(result == 42);
+  Expect.isTrue(field == 42);
+  Expect.isTrue(getField == 42);
+
+  result = (setField = 99);
+  Expect.isTrue(result == 99);
+  Expect.isTrue(field == 99);
+  Expect.isTrue(getField == 99);
+}