Add getClassList RPC

runtime/observatory/test/classes_test.dart

Index: runtime/observatory/test/classes_test.dart
diff --git a/runtime/observatory/test/classes_test.dart b/runtime/observatory/test/classes_test.dart
index 55d834b1626ad0b971a3a6c7145b7210a24118b5..4e200ce256e562e73b98c5b9bc4f0eb4e31172be 100644
--- a/runtime/observatory/test/classes_test.dart
+++ b/runtime/observatory/test/classes_test.dart
@@ -9,11 +9,17 @@ import 'test_helper.dart';
 var tests = [
 
 (Isolate isolate) =>
+  isolate.getClassHierarchy().then((Class o) {
+    expect(o.name, equals('Object'));
+}),
+
+(Isolate isolate) =>
   isolate.get('classes/62').then((Class c) {
     expect(c.name, equals('_List'));
     expect(c.vmCid, equals(62));
 }),
 
+
 ];
 
 main(args) => runIsolateTests(args, tests);