Revert "Add "last" setter to List."

sdk/lib/internal/list.dart

 // Copyright (c) 2013, 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._internal;
 
 /**
  * Mixin that throws on the length changing operations of [List].
  *
  * Intended to mix-in on top of [ListMixin] for fixed-length lists.
@@ skipping 92 matching lines @@
     throw new UnsupportedError(
         "Cannot modify an unmodifiable list");
   }
 
   /** This operation is not supported by an unmodifiable list. */
   void set length(int newLength) {
     throw new UnsupportedError(
         "Cannot change the length of an unmodifiable list");
   }
 
-  void set last(E value) {
-    throw new UnsupportedError(
-        "Cannot modify an unmodifiable list");
-  }
-
   /** This operation is not supported by an unmodifiable list. */
   void setAll(int at, Iterable<E> iterable) {
     throw new UnsupportedError(
         "Cannot modify an unmodifiable list");
   }
 
   /** This operation is not supported by an unmodifiable list. */
   void add(E value) {
     throw new UnsupportedError(
       "Cannot add to an unmodifiable list");
@@ skipping 244 matching lines @@
  * or become empty or been otherwise modified.
  * It will still be a valid object, so references to it will not, e.g., crash
  * the runtime if accessed, but no promises are made wrt. its contents.
  *
  * This unspecified behavior is the reason the function is not exposed to
  * users. We allow the underlying implementation to make the most efficient
  * conversion, at the cost of leaving the original list in an unspecified
  * state.
  */
 external List makeListFixedLength(List growableList);