Move kernel baseline tests to front_end.

pkg/front_end/testcases/rasta/unresolved_recovery.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.
 
 class E {
   foo() {
     super[4] = 42;
     super[4] += 5;
     return super[2];
   }
 }
 
 beforeTestMissingTry () {
   // Referring to this function before it has been resolved would lead to a
   // crash.
   testMissingTry();
 }
 
 testMissingTry() {
   on Exception catch (e) { }
 }
 
 main() {
 }