Fix small spec violation in String.prototype.split.

src/string.js

 // Copyright 2012 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 598 matching lines @@
 
 // ECMA-262 section 15.5.4.14
 function StringSplit(separator, limit) {
   if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
     throw MakeTypeError("called_on_null_or_undefined",
                         ["String.prototype.split"]);
   }
   var subject = TO_STRING_INLINE(this);
   limit = (IS_UNDEFINED(limit)) ? 0xffffffff : TO_UINT32(limit);
 
-  // ECMA-262 says that if separator is undefined, the result should
-  // be an array of size 1 containing the entire string.
-  if (IS_UNDEFINED(separator)) {
-    return [subject];
-  }
-
   var length = subject.length;
   if (!IS_REGEXP(separator)) {
-    separator = TO_STRING_INLINE(separator);
+    var separator_string = TO_STRING_INLINE(separator);
 
     if (limit === 0) return [];
 
-    var separator_length = separator.length;
+    // ECMA-262 says that if separator is undefined, the result should
+    // be an array of size 1 containing the entire string.
+    if (IS_UNDEFINED(separator)) return [subject];
+
+    var separator_length = separator_string.length;
 
     // If the separator string is empty then return the elements in the subject.
     if (separator_length === 0) return %StringToArray(subject, limit);
 
-    var result = %StringSplit(subject, separator, limit);
+    var result = %StringSplit(subject, separator_string, limit);
 
     return result;
   }
 
   if (limit === 0) return [];
 
   // Separator is a regular expression.
   return StringSplitOnRegExp(subject, separator, limit, length);
 }
 
@@ skipping 360 matching lines @@
     "fixed", StringFixed,
     "italics", StringItalics,
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup
   ));
 }
 
 SetUpString();