Revert "Add "last" setter to List."

tests/corelib/list_test.dart

Index: tests/corelib/list_test.dart
diff --git a/tests/corelib/list_test.dart b/tests/corelib/list_test.dart
index e8756a2e2c9b6846c82b90d722d2e4cb64015cf4..5187ee84ccce4cb210548b52923e1db406914798 100644
--- a/tests/corelib/list_test.dart
+++ b/tests/corelib/list_test.dart
@@ -45,12 +45,6 @@ void main() {
   testTypedGrowableList(new Uint32List(0).toList());
   testTypedGrowableList(new Int32List(0).toList());
 
-  // Lists based on ListBase and ListMixin.
-  testGrowableList(new BaseList());
-  testGrowableList(new BaseList().toList());
-  testGrowableList(new MixinList());
-  testGrowableList(new MixinList().toList());
-
   testListConstructor();
 }
 
@@ -76,23 +70,6 @@ void testTypedLengthInvariantOperations(List list) {
     list[i] = i;
   }
 
-  // last=
-  Expect.listEquals([0, 1, 2, 3], list);
-  list.last = 47;
-  Expect.listEquals([0, 1, 2, 47], list);
-  list.last -= 5;
-  Expect.listEquals([0, 1, 2, 42], list);
-  list.last++;
-  Expect.listEquals([0, 1, 2, 43], list);
-  ++list.last;
-  Expect.listEquals([0, 1, 2, 44], list);
-  list.last--;
-  Expect.listEquals([0, 1, 2, 43], list);
-  --list.last;
-  Expect.listEquals([0, 1, 2, 42], list);
-  list.last = 3;
-  Expect.listEquals([0, 1, 2, 3], list);
-
   // indexOf, lastIndexOf
   for (int i = 0; i < 4; i++) {
     Expect.equals(i, list[i]);
@@ -527,15 +504,3 @@ void testListConstructor() {
   Expect.throws(() { new List.filled(-2, 42); });  // Not negative.
   Expect.throws(() { new List.filled(null, 42); });  // Not null.
 }
-
-abstract class ListImpl<E>{
-  List _base = [];
-  int get length => _base.length;
-  void set length(int length) { _base.length = length; }
-  E operator[](int index) => _base[index];
-  void operator[]=(int index, E value) { _base[index] = value; }
-}
-
-class BaseList<E> = ListBase<E> with ListImpl<E>;
-
-class MixinList<E> = ListImpl<E> with ListMixin<E>;