Revert "Add "last" setter to List."

runtime/lib/growable_array.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.
 
 class _GrowableList<T> implements List<T> {
   static final int _classId = (new _GrowableList(0))._cid;
 
   void insert(int index, T element) {
     if (index < 0 || index > length) {
       throw new RangeError.range(index, 0, length);
@@ skipping 138 matching lines @@
   }
 
   void _setLength(int new_length) native "GrowableList_setLength";
 
   void _setData(_List array) native "GrowableList_setData";
 
   T operator [](int index) native "GrowableList_getIndexed";
 
   void operator []=(int index, T value) native "GrowableList_setIndexed";
 
-  void set last(T value) {
-    if (length == 0) throw IterableElementError.noElement();
-    this[length - 1] = value;
-  }
-
   // The length of this growable array. It is always less than or equal to the
   // length of the object array, which itself is always greater than 0, so that
   // grow() does not have to check for a zero length object array before
   // doubling its size.
   void add(T value) {
     var len = length;
     if (len == _capacity) {
       _grow(len * 2);
     }
     _setLength(len + 1);
@@ skipping 169 matching lines @@
   }
 
   Set<T> toSet() {
     return new Set<T>.from(this);
   }
 
   Map<int, T> asMap() {
     return IterableMixinWorkaround.asMapList(this);
   }
 }