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

tests/language/vm/optimized_testsmi_test.dart

 // Copyright (c) 2013, 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
 
 // Test branch optimization for TestSmiInstr
 
 import "package:expect/expect.dart";
 
 test1(a, bool b) {
   if (b) {
     a++;
   } else {
     a += 2;
@@ skipping 32 matching lines @@
   Expect.equals("even", test(0, false));
 }
 
 main() {
   run(test1);
   run(test2);
   run(test3);
   run(test4);
 }