Move dromaeo to third_party

samples/third_party/dromaeo/tests/dom-traverse.dart

 #library("dom-traverse.dart");
 #import("dart:dom");
-#import('../../common/common.dart');
+#import('../common/common.dart');
 #import('runner.dart');
 
 
 void main() {
   final int num = 40;
 
   // Try to force real results.
   var ret;
 
   String html = document.body.innerHTML;
@@ skipping 47 matching lines @@
       for (int i = 0; i < num * 2; i++) {
         Node cur = document.body.firstChild;
         while (cur !== null) {
           cur = cur.nextSibling;
         }
         ret = cur;
       }
     })
     .test('previousSibling', () {
       for (int i = 0; i < num * 2; i++) {
-        Node cur = document.body.firstChild;
+        Node cur = document.body.lastChild;
         while (cur !== null) {
           cur = cur.previousSibling;
         }
         ret = cur;
       }
     })
     .test('childNodes', () {
       for (int i = 0; i < num; i++) {
         final nodes = document.body.childNodes;
         for (int j = 0; j < nodes.length; j++) {
           ret = nodes[j];
         }
       }
     })
     .end();
 }