MDEV-26273 InnoDB FTS DDL fails when innodb_force_recovery is set to 2

InnoDB DDL fails when it tries to sync the table
when innodb_force_recovery is set to 2. Problem
is that fts_optimize_wq is not initialized when
there are no background threads. fts_sync_during_ddl()
should check whether fts_optimize_wq is initialized.

mysql-test/suite/innodb_fts/r/sync.result

@@ -145,3 +145,13 @@ id	title
 2	database
 3	good
 DROP TABLE t1;
+#
+# MDEV-26273 InnoDB fts DDL fails when
+# innodb_force_recovery is set to 2
+#
+# restart: --innodb_force_recovery=2
+CREATE TABLE t1 (FTS_DOC_ID BIGINT UNSIGNED KEY,
+f1 CHAR(200)) ENGINE=InnoDB;
+ALTER TABLE t1 ADD FULLTEXT INDEX(f1);
+DROP TABLE t1;
+# restart

mysql-test/suite/innodb_fts/t/sync.test

@@ -170,3 +170,17 @@ SET GLOBAL innodb_ft_aux_table=default;
 SELECT * FROM t1 WHERE MATCH(title) AGAINST ('mysql database good');
 
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-26273 InnoDB fts DDL fails when
+--echo # innodb_force_recovery is set to 2
+--echo #
+
+let $restart_parameters=--innodb_force_recovery=2;
+--source include/restart_mysqld.inc
+CREATE TABLE t1 (FTS_DOC_ID BIGINT UNSIGNED KEY,
+                 f1 CHAR(200)) ENGINE=InnoDB;
+ALTER TABLE t1 ADD FULLTEXT INDEX(f1);
+DROP TABLE t1;
+let $restart_parameters=;
+--source include/restart_mysqld.inc

storage/innobase/fts/fts0opt.cc

@@ -3037,6 +3037,8 @@ fts_optimize_shutdown()
 @param[in]	table	table to be synced */
 void fts_sync_during_ddl(dict_table_t* table)
 {
+  if (!fts_optimize_wq)
+    return;
   mutex_enter(&fts_optimize_wq->mutex);
   if (!table->fts->sync_message)
   {