Fix small spec violation in String.prototype.split.

test/mjsunit/string-split.js

 // Copyright 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 127 matching lines @@
 var all_ascii_codes = [];
 for (var i = 0; i < 128; i++) all_ascii_codes[i] = i;
 var all_ascii_string = String.fromCharCode.apply(String, all_ascii_codes);
 
 var split_chars = all_ascii_string.split("");
 assertEquals(128, split_chars.length);
 for (var i = 0; i < 128; i++) {
   assertEquals(1, split_chars[i].length);
   assertEquals(i, split_chars[i].charCodeAt(0));
 }
+
+// Check that the separator is converted to string before returning due to
+// limit == 0.
+var counter = 0;
+var separator = { toString: function() { counter++; return "b"; }};
+assertEquals([], "abc".split(separator, 0));
+assertEquals(1, counter);
+
+// Check that the subject is converted to string before the separator.
+counter = 0;
+var subject = { toString: function() { assertEquals(0, counter);
+                                       counter++;
+                                       return "abc"; }};
+separator = { toString: function() { assertEquals(1, counter);
+                                     counter++;
+                                     return "b"; }};
+
+assertEquals(["a", "c"], String.prototype.split.call(subject, separator));
+assertEquals(2, counter);