Update V8 to r6768 as required by WebKit r78450

Change-Id: Ib8868ff7147a76547a8d1d85f257ebe8546a3d3f
diff --git a/test/mjsunit/regress/regress-900966.js b/test/mjsunit/regress/regress-900966.js
index acffe75..99603c1 100644
--- a/test/mjsunit/regress/regress-900966.js
+++ b/test/mjsunit/regress/regress-900966.js
@@ -37,6 +37,8 @@
 }
 f();
 f();
+f();
+f();
 
 assertTrue(2[11] === undefined);
 Number.prototype[11] = 'y';