Reduce service isolate startup time from ~80ms to ~30ms

runtime/bin/vmservice/resources.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.
 
 part of vmservice_io;
 
 String detectMimeType(String name) {
   var extensionStart = name.lastIndexOf('.');
   var extension = name.substring(extensionStart+1);
   switch (extension) {
@@ skipping 26 matching lines @@
   Resource(this.name, this.mimeType, this.data);
   static final Map<String, Resource> resources = new Map<String, Resource>();
 }
 
 
 void _addResource(String name, List<int> data) {
   var mimeType = detectMimeType(name);
   Resource resource = new Resource(name, mimeType, data);
   Resource.resources[name] = resource;
 }
+
+void _triggerResourceLoad() native "VMServiceIO_TriggerResourceLoad";