Add mirrors tests

test/codegen/lib/mirrors/reflectively_instantiate_uninstantiated_class_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.
+
+// Ensure that otherwise uninstantiated classes can be instantiated
+// reflectively.
+
+import "dart:mirrors";
+
+class Foo {
+  int a;
+}
+
+main() {
+  // Do NOT instantiate Foo.
+  var m = reflectClass(Foo);
+  var instance = m.newInstance(const Symbol(''), []);
+  print(instance);
+  bool threw = false;
+  try {
+    m.newInstance(#noSuchConstructor, []);
+    throw 'Expected an exception';
+  } on NoSuchMethodError catch (e) {
+    print(e);
+    threw = true;
+  }
+  if (!threw) throw 'Expected a NoSuchMethodError';
+}