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

tests/language/bit_shift_test.dart

Index: tests/language/bit_shift_test.dart
diff --git a/tests/language/bit_shift_test.dart b/tests/language/bit_shift_test.dart
index 8493936982f03549ff8a3fa750572548e2627b8f..e797ea3131b8ea8e37b5b2125014567183d9946a 100644
--- a/tests/language/bit_shift_test.dart
+++ b/tests/language/bit_shift_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2012, 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";