Update V8 to r5318 to fix crashing ARM bugs

Bug: 2947054
Change-Id: I9c7398edb1525477c75ace9d383efaf790d12c51
diff --git a/src/arm/codegen-arm.h b/src/arm/codegen-arm.h
index 8a632a9..e550a62 100644
--- a/src/arm/codegen-arm.h
+++ b/src/arm/codegen-arm.h
@@ -528,6 +528,8 @@
 
   void GenerateRegExpConstructResult(ZoneList<Expression*>* args);
 
+  void GenerateRegExpCloneResult(ZoneList<Expression*>* args);
+
   // Support for fast native caches.
   void GenerateGetFromCache(ZoneList<Expression*>* args);