Added %NeverOptimize runtime call that can disable optimizations for a method for tests.

test/mjsunit/regress/regress-1713b.js

 // Copyright 2011 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 65 matching lines @@
 
   for (var i = 0; i < 1e4; i++) CreateCode(i);
   gc();
   gc();
   gc();
 
   print(">>> 1 <<<");
 
   L.execute(O);
 
-  try {} catch (e) {}
+  %NeverOptimize();
 
   L = null;
   print(">>> 2 <<<");
   AllocateXMb(8);
  //rint("1");
  //llocateXMb(8);
  //rint("1");
  //llocateXMb(8);
 
 }
@@ skipping 21 matching lines @@
 var O1 = {};
 var O2 = {};
 var O3 = {};
 var O4 = {f:0};
 
 foo(O1, false);
 foo(O2, false);
 foo(O3, false);
 %OptimizeFunctionOnNextCall(foo);
 foo(O4, true);