Support --use-kernel in memory_compiler

tests/compiler/dart2js/kernel/getters_setters_test.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 file.
 
 import 'package:test/test.dart';
 
 import 'helper.dart' show check;
 
 main() {
   group('compile getters with kernel', () {
@@ skipping 100 matching lines @@
 }
 
 class B extends A {
   bar() {
     super.ferocious = 87;
   }
 }
 main() {
   new B().bar();
 }''';
-    return check(code);
+    return check(code, useKernelInSsa: true);
   });
 }