Re-land beginning Dart 2.0 test migration.

tests/language_strong/abstract_getter_test.dart

-// Copyright (c) 2012, 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 "package:expect/expect.dart";
-
-// Test to ensure that an abstract getter is not mistaken for a field.
-
-class Foo {
-  // Intentionally abstract:
-  get i; // //# 01: static type warning
-}
-
-class Bar {}
-
-noMethod(e) => e is NoSuchMethodError;
-
-checkIt(f) {
-  Expect.throws(() { f.i = 'hi'; }, noMethod); // //# 01: continued
-  Expect.throws(() { print(f.i); }, noMethod); // //# 01: continued
-  Expect.throws(() { print(f.i()); }, noMethod); // //# 01: continued
-}
-
-main() {
-  checkIt(new Foo());
-  checkIt(new Bar());
-}