pg_dump: free temporary variable qualTmpExtTable

This part of codes are not covered by PR pipeline, tested manually.

src/bin/pg_dump/pg_dump.c

@@ -14566,6 +14566,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 
 				appendPQExpBuffer(q, "\n");
 				free(relname);
+				free(qualTmpExtTable);
 			}
 
 			PQclear(res);