Add inference test functionality based on code point id.

tests/compiler/dart2js/inference/send_test.dart

+// Copyright (c) 2017, 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:async_helper/async_helper.dart';
+import 'inference_test_helper.dart';
+
+const List<String> TESTS = const <String>[
+  '''
+class Super {
+  var field = 42;
+}
+class Sub extends Super {
+  method() {
+   var a = super.field = new Sub();
+   return a.@{[exact=Sub]}method;
+  }
+}
+main() {
+  new Sub().@{[exact=Sub]}method();
+}
+''',
+];
+
+main() {
+  asyncTest(() async {
+    for (String annotatedCode in TESTS) {
+      await checkCode(annotatedCode);
+    }
+  });
+}