Turn on parallel recompilation for tests that assert optimization status.

test/mjsunit/regress/regress-2451.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 19 matching lines @@
 function f() {
   assertEquals(-1.0, Math.round(-1.5));
   assertEquals(-2.0, Math.round(-2.5));
   assertEquals(-1.0, Math.round(-0.5000000000000001));
 }
 
 f();
 f();
 %OptimizeFunctionOnNextCall(f);
 f();
-assertTrue(%GetOptimizationStatus(f) != 2);
-
+assertOptimized(f);