MDEV-30542 Add multilength spider self-reference detection test

storage/spider/mysql-test/spider/bugfix/r/self_reference_multi.result

+for master_1
+for child2
+for child3
+
+MDEV-6268 SPIDER table with no COMMENT clause causes queries to wait forever
+
+CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$MASTER_1_MYSOCK", DATABASE 'test',user 'root');
+create table t2 (c int);
+create table t1 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t2"';
+create table t0 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t1"';
+alter table t2 ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t0"';
+select * from t0;
+ERROR HY000: An infinite loop is detected when opening table test.t0
+select * from t1;
+ERROR HY000: An infinite loop is detected when opening table test.t0
+select * from t2;
+ERROR HY000: An infinite loop is detected when opening table test.t0
+drop table t0, t1, t2;
+for master_1
+for child2
+for child3

storage/spider/mysql-test/spider/bugfix/t/self_reference_multi.test

+--disable_query_log
+--disable_result_log
+--source ../../t/test_init.inc
+--enable_result_log
+--enable_query_log
+
+--echo
+--echo MDEV-6268 SPIDER table with no COMMENT clause causes queries to wait forever
+--echo
+
+--replace_regex /SOCKET ".*"/SOCKET "$MASTER_1_MYSOCK"/
+eval CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$MASTER_1_MYSOCK", DATABASE 'test',user 'root');
+create table t2 (c int);
+create table t1 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t2"';
+create table t0 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t1"';
+alter table t2 ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t0"';
+--error 12719
+select * from t0;
+--error 12719
+select * from t1;
+--error 12719
+select * from t2;
+drop table t0, t1, t2;
+
+--disable_query_log
+--disable_result_log
+--source ../../t/test_deinit.inc
+--enable_result_log
+--enable_query_log