Ensure that ToPositiveInteger is optimizable.

src/runtime.js

 // Copyright 2006-2008 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 647 matching lines @@
   if (IS_SPEC_FUNCTION(valueOf)) {
     var v = %_CallFunction(x, valueOf);
     if (%IsPrimitive(v)) return v;
   }
 
   throw %MakeTypeError('cannot_convert_to_primitive', []);
 }
 
 function ToPositiveInteger(x, rangeErrorName) {
   var i = TO_INTEGER(x);
-  if (i < 0) throw %MakeRangeError(rangeErrorName);
+  if (i < 0) throw MakeRangeError(rangeErrorName);
   return i;
 }
 
 
 // NOTE: Setting the prototype for Array must take place as early as
 // possible due to code generation for array literals.  When
 // generating code for a array literal a boilerplate array is created
 // that is cloned when running the code.  It is essential that the
 // boilerplate gets the right prototype.
 %FunctionSetPrototype($Array, new $Array(0));