observatory: populate 'architecture' in VM, and add numerical vmId in Class.

runtime/bin/vmservice/observatory/test/classes_test.dart

Index: runtime/bin/vmservice/observatory/test/classes_test.dart
===================================================================
--- runtime/bin/vmservice/observatory/test/classes_test.dart	(revision 0)
+++ runtime/bin/vmservice/observatory/test/classes_test.dart	(working copy)
@@ -0,0 +1,19 @@
+// Copyright (c) 2014, 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:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+
+var tests = [
+
+(Isolate isolate) =>
+  isolate.get('classes/62').then((Class c) {
+    expect(c.name, equals('_List'));
+    expect(c.vmCid, equals(62));
+}),
+
+];
+
+main(args) => runIsolateTests(args, tests);