Revert "Change some platform libraries to use `part of URI`."

sdk/lib/collection/iterator.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-part of "dart:collection";
+part of dart.collection;
 
 /**
  * The [HasNextIterator] class wraps an [Iterator] and provides methods to
  * iterate over an object using `hasNext` and `next`.
  *
  * An [HasNextIterator] does not implement the [Iterator] interface.
  */
 class HasNextIterator<E> {
   static const int _HAS_NEXT_AND_NEXT_IN_CURRENT = 0;
   static const int _NO_NEXT = 1;
@@ skipping 20 matching lines @@
   }
 
   void _move() {
     if (_iterator.moveNext()) {
       _state = _HAS_NEXT_AND_NEXT_IN_CURRENT;
     } else {
       _state = _NO_NEXT;
     }
   }
 }