Fix bugs in GrowableList.remove*.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index d40197e46e52bfdcdfebcc03299a82637090409f..8d8922b6761ab56719ddb60ca5b44ff9f0b035bf 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -8073,19 +8073,19 @@ class _ChildrenElementList implements List {
   }
 
   void removeAll(Iterable elements) {
-    Collections.removeAll(this, elements);
+    IterableMixinWorkaround.removeAll(this, elements);
   }
 
   void retainAll(Iterable elements) {
-    Collections.retainAll(this, elements);
+    IterableMixinWorkaround.retainAll(this, elements);
   }
 
   void removeMatching(bool test(Element element)) {
-    Collections.removeMatching(this, test);
+    IterableMixinWorkaround.removeMatching(this, test);
   }
 
   void retainMatching(bool test(Element element)) {
-    Collections.retainMatching(this, test);
+    IterableMixinWorkaround.retainMatching(this, test);
   }
 
   void removeRange(int start, int rangeLength) {