Remove useless debug assertion

The debug assertion assumes that the table definition is always in the
binlogs. If a binlog row event without a table definition is read, debug
versions would crash even though the situation is acceptable and expected.

server/modules/routing/avrorouter/avro_rbr.c

@@ -272,7 +272,6 @@ bool handle_row_event(AVRO_INSTANCE *router, REP_HEADER *hdr, uint8_t *ptr)
     /** There should always be a table map event prior to a row event.
      * TODO: Make the active_maps dynamic */
     TABLE_MAP *map = router->active_maps[table_id % sizeof(router->active_maps)];
-    ss_dassert(map);
 
     if (map)
     {