fix custom_elements_test on ie10

tests/html/custom_elements_test.dart

Index: tests/html/custom_elements_test.dart
diff --git a/tests/html/custom_elements_test.dart b/tests/html/custom_elements_test.dart
index 07111b5179cada6c372135f83e8816a98ed9eaf2..bbd3ce75cbd75d1d87b45415da5f668a1610e98e 100644
--- a/tests/html/custom_elements_test.dart
+++ b/tests/html/custom_elements_test.dart
@@ -38,18 +38,6 @@ String get nextTag => 'x-type${nextTagId++}';
 
 class NotAnElement {}
 
-loadPolyfills() {
-  if (!document.supportsRegister) {
-    // Cache blocker is a workaround for:
-    // https://code.google.com/p/dart/issues/detail?id=11834
-    var cacheBlocker = new DateTime.now().millisecondsSinceEpoch;
-    return HttpRequest.getString('/root_dart/pkg/custom_element/lib/'
-      'custom-elements.debug.js?cacheBlock=$cacheBlocker').then((code) {
-      document.head.children.add(new ScriptElement()..text = code);
-    });
-  }
-}
-
 main() {
   useHtmlIndividualConfiguration();