Merge V8 at 3.7.12.28

Bug: 5688872

Change-Id: Iddb40cae44d51a2b449f2858951e0472771f5981
diff --git a/test/mjsunit/string-externalize.js b/test/mjsunit/string-externalize.js
index da89786..d52a7e2 100644
--- a/test/mjsunit/string-externalize.js
+++ b/test/mjsunit/string-externalize.js
@@ -44,7 +44,7 @@
   assertFalse(isAsciiString(twoByteExternalWithAsciiData));
 
   var realTwoByteExternalString =
-      "\u1234\u1234" + (function() { return "\u1234"; })();
+      "\u1234\u1234\u1234\u1234" + (function() { return "\u1234"; })();
   externalizeString(realTwoByteExternalString);
   assertFalse(isAsciiString(realTwoByteExternalString));