Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/switch_execution_case_t02.dart

 /*
  * Copyright (c) 2011, 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.
  */
 
 // Slightly modified copy of
 // `co19/src/Language/Statements/Switch/execution_case_t02.dart`.
 
 /**
@@ skipping 40 matching lines @@
     case 5:
     case 6:
     default:
   }
 
   return result;
 }
 
 main() {
 }