Migrated test block 13 to Dart 2.0.

tests/corelib_2/list_first_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";
 
 void test(List list) {
   if (list.isEmpty) {
     Expect.throws(() => list.first, (e) => e is StateError);
   } else {
     Expect.equals(list[0], list.first);
   }
 }
 
 main() {
   test([1, 2, 3]);
   test(const ["foo", "bar"]);
   test([]);
   test(const []);
 }