Move kernel baseline tests to front_end.

pkg/front_end/testcases/function_type_recovery.dart

 // Copyright (c) 2017, 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 that an inline function type inside a `Function` type isn't a
 // parser error.
 
 typedef F = int Function(int f(String x));
 
 main() {
   F f = null;
   String Function(String g(int y)) g = null;
 }