Add mirrors tests

test/codegen/lib/mirrors/mirrors_resolve_fields_test.dart

+// Copyright (c) 2013, 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.
+
+// Regression test for dart2js that used to not resolve instance
+// fields when a class is only instantiated through mirrors.
+
+import "package:expect/expect.dart";
+import 'dart:mirrors';
+
+class A {
+  static const int _STATE_INITIAL = 0;
+  int _state = _STATE_INITIAL;
+  A();
+}
+
+main() {
+  var mirrors = currentMirrorSystem();  
+  var classMirror = reflectClass(A);
+  var instanceMirror = classMirror.newInstance(const Symbol(''), []);
+  Expect.equals(A._STATE_INITIAL, instanceMirror.reflectee._state);
+}