Make reflectClass(dynamic) throw an illegal argument exception.

tests/lib/mirrors/hierarchy_invariants_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.
+
+library test.hierarchy_invariants_test;
+
+import 'dart:mirrors';
+
+import 'package:expect/expect.dart';
+
+check(classMirror) {
+  if (classMirror is TypedefMirror) return;
+
+  Expect.isTrue(classMirror.simpleName is Symbol);
+  Expect.notEquals(null, classMirror.owner);
+  Expect.isTrue(classMirror.owner is LibraryMirror);
+  Expect.isTrue(classMirror.superinterfaces is List);
+  if (classMirror.superclass == null) {
+    Expect.equals(reflectClass(Object), classMirror);
+  } else {
+    check(classMirror.superclass);
+  }
+}
+
+main() {
+  currentMirrorSystem().libraries.values.forEach((libraryMirror) {
+    libraryMirror.classes.values.forEach((classMirror) {
+      check(classMirror);
+    });
+  });
+
+  Expect.throws(() => reflectClass(dynamic),
+                (e) => e is ArgumentError,
+                'dynamic is not a class');
+}