Revert "Build Observatory with runtime"

runtime/bin/vmservice/observatory/lib/service_io.dart

 // 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.
 
 library service_io;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:typed_data';
 
@@ skipping 46 matching lines @@
                           data.lengthInBytes));
   }
 }
 
 /// The [WebSocketVM] communicates with a Dart VM over WebSocket. The Dart VM
 /// can be embedded in Chromium or standalone. In the case of Chromium, we
 /// make the service requests via the Chrome Remote Debugging Protocol.
 class WebSocketVM extends CommonWebSocketVM {
   WebSocketVM(WebSocketVMTarget target) : super(target, new _IOWebSocket());
 }