Print new RelOptInfo field top_parent_relids in outfuncs.c

I intended to include this adjustment in the previous commit
(7a39b5e40) but messed up.

src/backend/nodes/outfuncs.c

@@ -2250,6 +2250,7 @@ _outRelOptInfo(StringInfo str, const RelOptInfo *node)
 	WRITE_UINT_FIELD(baserestrict_min_security);
 	WRITE_NODE_FIELD(joininfo);
 	WRITE_BOOL_FIELD(has_eclass_joins);
+	WRITE_BITMAPSET_FIELD(top_parent_relids);
 }
 
 static void