Add function stub to native result to solve broken test

lib/native/result.js

@@ -19,3 +19,10 @@ NativeResult.prototype.addCommandComplete = function(pq) {
     });
   }
 };
+
+NativeResult.prototype.addRow = function(row) {
+  // This is empty to ensure pg code doesn't break when switching to pg-native
+  // pg-native loads all rows into the final result object by default.
+  // This is because libpg loads all rows into memory before passing the result
+  // to pg-native.
+};