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

tests/language/instanceof4_test.dart

Index: tests/language/instanceof4_test.dart
diff --git a/tests/language/instanceof4_test.dart b/tests/language/instanceof4_test.dart
index 86282dabb06505d53cee648cf29ce537db806557..be5a068c8d71fac9201a3fce78a6476b6adc7d7c 100644
--- a/tests/language/instanceof4_test.dart
+++ b/tests/language/instanceof4_test.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 // Dart test program for testing the instanceof operation.
 // Regression test for issue 5216.
-// VMOptions=--optimization-counter-threshold=10 --no-use-osr
+// VMOptions=--optimization-counter-threshold=10 --no-use-osr --no-background-compilation
 
 import "package:expect/expect.dart";