Add --no-background-compilation to tests that expect to run code in optimized form

tests/language/vm/uint32_right_shift_test.dart

Index: tests/language/vm/uint32_right_shift_test.dart
diff --git a/tests/language/vm/uint32_right_shift_test.dart b/tests/language/vm/uint32_right_shift_test.dart
index 6c7ae5f29cffe51453661efa53f075e075366c84..d44b84e49ad19bc7f5a8b8fda48b572af2cb317d 100644
--- a/tests/language/vm/uint32_right_shift_test.dart
+++ b/tests/language/vm/uint32_right_shift_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2014, 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.
-// VMOptions=--optimization_counter_threshold=10
+// VMOptions=--optimization_counter_threshold=10 --no-background_compilation
 
 import 'package:expect/expect.dart';