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

tests/language/identical_test.dart

Index: tests/language/identical_test.dart
diff --git a/tests/language/identical_test.dart b/tests/language/identical_test.dart
index 23be3adbe45afdd67d24c7b0c10f5fa5ed26841b..244f8149ef624029149716f8d7ebee1271426d80 100644
--- a/tests/language/identical_test.dart
+++ b/tests/language/identical_test.dart
@@ -2,7 +2,7 @@
 // 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.
 // Test efficient and correct implementation of !identical(a, b).
-// VMOptions=--optimization-counter-threshold=10
+// VMOptions=--optimization-counter-threshold=10 --no-background-compilation
 
 import 'package:expect/expect.dart';