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

tests/language/mul_recipr_test.dart

 // Copyright (c) 2015, 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.
 // Dart test program checking that optimizations are not too aggresive and
 // incorrect:
 // - (a * (1.0 / b))
 //
-// VMOptions=--optimization-counter-threshold=8 --no-use-osr
+// VMOptions=--optimization-counter-threshold=8 --no-use-osr --no-background-compilation
 
 import "package:expect/expect.dart";
 
 var xx = 23.0;
 
 main() {
   xx = 1e-6;
   scaleIt(1e-310);
   Expect.isTrue(xx.isInfinite);
   for (int i = 0; i < 10; i++) {
     xx = 24.0;
     scaleIt(6.0);
     Expect.equals(4.0, xx);
   }
   xx = 1e-6;
   scaleIt(1e-310);
   Expect.isTrue(xx.isInfinite);
 }
 
 scaleIt(double b) {
   scale(1.0 / b);
 }
 
 scale(a) {
   xx *= a;
 }