Revert "Add "last" setter to List."

pkg/collection/test/wrapper_test.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.
 
 /// Tests wrapper utilities.
 
 import "dart:collection";
 import "package:collection/collection.dart";
 import "package:unittest/unittest.dart";
 
@@ skipping 179 matching lines @@
     expect.addAll([val]).equals.addAll([val]);
     expect.asMap().equals.asMap();
     expect.clear().equals.clear();
     expect.fillRange(4, 5, null).equals.fillRange(4, 5);
     expect.fillRange(4, 5, val).equals.fillRange(4, 5, val);
     expect.getRange(4, 5).equals.getRange(4, 5);
     expect.indexOf(val, 0).equals.indexOf(val);
     expect.indexOf(val, 4).equals.indexOf(val, 4);
     expect.insert(4, val).equals.insert(4, val);
     expect.insertAll(4, [val]).equals.insertAll(4, [val]);
-    (expect..last = 5).equals.last = 5;
     expect.lastIndexOf(val, null).equals.lastIndexOf(val);
     expect.lastIndexOf(val, 4).equals.lastIndexOf(val, 4);
     (expect..length = 4).equals.length = 4;
     expect.remove(val).equals.remove(val);
     expect.removeAt(4).equals.removeAt(4);
     expect.removeLast().equals.removeLast();
     expect.removeRange(4, 5).equals.removeRange(4, 5);
     expect.removeWhere(func1).equals.removeWhere(func1);
     expect.replaceRange(4, 5, [val]).equals.replaceRange(4, 5, [val]);
     expect.retainWhere(func1).equals.retainWhere(func1);
@@ skipping 445 matching lines @@
 
     test(".retainWhere", () {
       map["f"] = "foo";
       map["b"] = "bar";
       map["q"] = "qoo";
       set.retainWhere((element) => element.endsWith("o"));
       expect(map, equals({"f": "foo", "q": "qoo"}));
     });
   });
 }