Fix overflow in WriteQuoteJsonString and SlowQuoteJsonString

test/mjsunit/regress/regress-latin-1.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 58 matching lines @@
 
 // Unicode equivalence
 assertTrue(/\u039c/i.test('\u00b5'));
 assertTrue(/\u039c/i.test('\u03bc'));
 assertTrue(/\u00b5/i.test('\u03bc'));
 // Unicode equivalence ranges
 assertTrue(/[\u039b-\u039d]/i.test('\u00b5'));
 assertFalse(/[^\u039b-\u039d]/i.test('\u00b5'));
 assertFalse(/[\u039b-\u039d]/.test('\u00b5'));
 assertTrue(/[^\u039b-\u039d]/.test('\u00b5'));
+
+// Check a regression in QuoteJsonSlow and WriteQuoteJsonString
+for (var testNumber = 0; testNumber < 2; testNumber++) {
+  var testString = "\xdc";
+  var loopLength = testNumber == 0 ? 0 : 20;  
+  for (var i = 0; i < loopLength; i++ ) {
+    testString += testString;
+  }
+  var stringified = JSON.stringify({"test" : testString}, null, 0);
+  var stringifiedExpected = '{"test":"' + testString + '"}';
+  assertEquals(stringifiedExpected, stringified);
+}