Fix some corelib tests.

tests/corelib/list_map_test.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.
 
 import "package:expect/expect.dart";
 
 main() {
   testOperations();
 }
 
 class ThrowMarker {
   const ThrowMarker();
   String toString() => "<<THROWS>>";
 }
 
 void testOperations() {
   // Comparison lists.
   List l = const [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
   List r = const [10, 9, 8, 7, 6, 5, 4, 3, 2, 1];
   // Function that reverses l and r lists when used to map.
   int rev(x) => 11 - x;
   // A base list that starts out like l, but isn't const.
-  Iterable base = l.map((x) => x).toList();
+  List base = l.map((x) => x).toList();
 
   Iterable reversed = l.map(rev);
 
   Expect.listEquals(r, l.map(rev).toList());
   Expect.listEquals(l, l.map(rev).map(rev).toList());
   for (int i = 0; i < r.length; i++) {
     Expect.equals(r[i], reversed.elementAt(i));
   }
   Expect.equals(4, base.indexOf(5));
   Expect.equals(5, reversed.toList().indexOf(5));
@@ skipping 121 matching lines @@
   testList([0, 1, 2, 3]);
   testList([3, 4, 5, 6]);
   testList([10, 11, 12, 13]);
   testList(l);
   testList(r);
   testList(base);
 
   // Reverse const list.
   Expect.listEquals(r, l.map(rev).toList());
 }