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

tests/language/vm/uint32_right_shift_test.dart

 // Copyright (c) 2014, 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
 
 import 'package:expect/expect.dart';
 
 trunc(x) => x & 0xFFFFFFFF;
 
 foo(t, x) => t(x >> 15);
 
 main() {
   for (var i = 0; i < 20000; i++) {
     Expect.equals(0x00010000, foo(trunc, 0x80000000));
   }
   for (var i = 0; i < 20000; i++) {
     Expect.equals(0x10000000, foo(trunc, 0x80000000000));
   }
 }