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

tests/standalone/slowpath_safepoints_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.
 // Test that safepoints associated with slowpaths don't mark non-existing values
 // alive.
-// VMOptions=--optimization-counter-threshold=5 --no-inline_alloc --gc_at_instance_allocation=_Double
+// VMOptions=--optimization-counter-threshold=5 --no-inline_alloc --gc_at_instance_allocation=_Double --no-background-compilation
 
 class C {
   final next;
   C(this.next);
 }
 
 
 noop(a1, a2, a3, a4, a5, a6, a7, a8, a9) => 0;
 
 crash(f, i) {
@@ skipping 23 matching lines @@
   f(d1, d2, d3, d4, d5, d6, d7, d8, d9);
   f(d1, d2, d3, d4, d5, d6, d7, d8, d9);
 }
 
 main() {
   for (var i = 0; i < 10; i++) {
     print(i);
     crash(noop, 10);
   }
 }