Spider table with charset utf32/utf16/ucs2 tries to set client charset to unsupported value

--source plugin/spider/spider/include/init_spider.inc

SET spider_same_server_link= on;

eval create server s foreign data wrapper mysql options (host "127.0.0.1", database "test", user "root", port $MASTER_MYPORT);

CREATE TABLE t (a INT);

CREATE TABLE t_spider (a INT) ENGINE=SPIDER COMMENT = "wrapper 'mysql', srv 's', table 't'" CHARSET utf32;

SELECT * FROM t_spider;

# Cleanup

DROP TABLE t_spider, t;

DROP SERVER s;

--source plugin/spider/spider/include/deinit_spider.inc

mysqltest: At line 8: query 'SELECT * FROM t_spider' failed: 1231: Variable 'character_set_client' can't be set to the value of 'utf32'