Update V8 to r5017 as required by WebKit r62496

Change-Id: I1b4b7718d1d77ceef07f543e9150a2cb3a628f3a
diff --git a/src/api.cc b/src/api.cc
index 464ca54..0f64dd4 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -2606,6 +2606,8 @@
     return;
   }
   i::Handle<i::PixelArray> pixels = i::Factory::NewPixelArray(length, data);
+  self->set_map(
+      *i::Factory::GetSlowElementsMap(i::Handle<i::Map>(self->map())));
   self->set_elements(*pixels);
 }
 
@@ -2659,6 +2661,8 @@
   }
   i::Handle<i::ExternalArray> array =
       i::Factory::NewExternalArray(length, array_type, data);
+  self->set_map(
+      *i::Factory::GetSlowElementsMap(i::Handle<i::Map>(self->map())));
   self->set_elements(*array);
 }