Update V8 to r4851 as required by WebKit r61121

Change-Id: Ib01b7c8e38d5b82b254192fc06365aa5b85780c5
diff --git a/test/mjsunit/string-charcodeat.js b/test/mjsunit/string-charcodeat.js
index 3927557..831f688 100644
--- a/test/mjsunit/string-charcodeat.js
+++ b/test/mjsunit/string-charcodeat.js
@@ -153,6 +153,10 @@
 TestStringType(Flat16, true);
 TestStringType(NotAString16, true);
 
+for (var i = 0; i != 10; i++) {
+  assertEquals(101, Cons16().charCodeAt(1.1));
+  assertEquals('e', Cons16().charAt(1.1));
+}
 
 function StupidThing() {
   // Doesn't return a string from toString!