Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/for_loop.dart

 // Copyright (c) 2016, 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.md file.
 
 main() {
   int c = new DateTime.now().millisecondsSinceEpoch;
   for (int i = 0; i < 100; i++) {
     print(i++);
   }
   for (int i = 0; i < 100; c < 42 ? throw "fisk" : i++) {
     print(i++);
   }
 }