Merge upstream V8 change to fix HasRealIndexedProperty.

Bug: 9720511
Change-Id: I731b49b1bfbeeb9927fb995342f9e7454ce834dc
diff --git a/src/objects.cc b/src/objects.cc
index 904cf52..a30641b 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10102,6 +10102,13 @@
     }
   }
 
+  if (IsJSGlobalProxy()) {
+    Object* proto = GetPrototype();
+    if (proto->IsNull()) return false;
+    ASSERT(proto->IsJSGlobalObject());
+    return JSObject::cast(proto)->HasRealElementProperty(index);
+  }
+
   // Handle [] on String objects.
   if (this->IsStringObjectWithCharacterAt(index)) return true;