Reapply remove setTimeout, take 3.

samples/third_party/dromaeo/tests/dom-modify-html.dart

 library dromaeo;
+import 'dart:async';
 import 'dart:html';
 import 'dart:json' as json;
 import 'dart:math' as Math;
 part 'Common.dart';
 part 'RunnerSuite.dart';
 
 void main() {
   final int num = 400;
   var random = new Math.Random();
 
@@ skipping 49 matching lines @@
     .test('appendChild', () {
       for (int i = 0; i < elems.length; i++)
         document.body.$dom_appendChild(elems[i]);
     })
     .test('insertBefore', () {
       for (int i = 0; i < elems.length; i++)
         document.body.insertBefore(elems[i], document.body.$dom_firstChild);
     })
     .end();
 }