Replaced Element.append with Node.appendChild

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

 library dromaeo;
 import 'dart:async';
 import 'dart:html';
 import '../common/common.dart';
 import 'dart:json' as json;
 import 'dart:math' as Math;
 part 'Common.dart';
 part 'RunnerSuite.dart';
 
 void main() {
@@ skipping 11 matching lines @@
         return 'id="test${group}${num}"';
       });
       html = BenchUtil.replaceAll(html, 'name="test.*?"', (Match match) {
         return 'name="test${num}"';
       });
       html = BenchUtil.replaceAll(html, 'class="foo.*?"', (Match match) {
         return 'class="foo test${num} bar"';
       });
       final div = new Element.tag('div');
       div.innerHtml = html;
-      document.body.$dom_appendChild(div);
+      document.body.append(div);
     })
     .test('getElementById', () {
       for (int i = 0; i < num * 30; i++) {
         ret = document.$dom_getElementById('testA$num').nodeType;
         ret = document.$dom_getElementById('testB$num').nodeType;
         ret = document.$dom_getElementById('testC$num').nodeType;
         ret = document.$dom_getElementById('testD$num').nodeType;
         ret = document.$dom_getElementById('testE$num').nodeType;
         ret = document.$dom_getElementById('testF$num').nodeType;
       }
@@ skipping 54 matching lines @@
       for (int i = 0; i < num * 20; i++) {
         ret = document.$dom_getElementsByName('test').length == 0;
         ret = document.$dom_getElementsByName('test').length == 0;
         ret = document.$dom_getElementsByName('test').length == 0;
         ret = document.$dom_getElementsByName('test').length == 0;
         ret = document.$dom_getElementsByName('test').length == 0;
       }
     })
     .end();
 }