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

tests/language/vm/math_vm_test.dart

 // 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.
 // Tests that the VM does not crash on weird corner cases of class Math.
-// VMOptions=--optimization_counter_threshold=100
+// VMOptions=--optimization_counter_threshold=100 --no-background_compilation
 
 library math_vm_test;
 
 import "package:expect/expect.dart";
 import 'dart:math';
 
 class FakeNumber {
   const FakeNumber();
   void toDouble() {}
 }
@@ skipping 37 matching lines @@
 main() {
   const double value = 1.54;
   final firstRes = testSinCos(value);
   for (int i = 0; i < 200; i++) {
     MathTest.testMain();
     testDoublePow();
     testSinCos(value);
   }
   Expect.equals(firstRes, testSinCos(value));
 }