MDEV-9137 MariaDB Crash on Query Using Aria Engine

fix for 2-level ft indexes and boolean search in Aria

mysql-test/suite/maria/fulltext2.result

@@ -18,5 +18,8 @@ test.t1	check	status	OK
 repair table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	repair	status	OK
+select count(*) from t1 where match a against ('aaaxxx' in boolean mode);
+count(*)
+1024
 insert t1 (a) values ('aaaxxx'),('aaayyy');
 drop table t1;

mysql-test/suite/maria/fulltext2.test

@@ -39,6 +39,8 @@ repair table t1;
 check table t1;
 repair table t1;
 
+select count(*) from t1 where match a against ('aaaxxx' in boolean mode);
+
 # mi_write:
 insert t1 (a) values ('aaaxxx'),('aaayyy');
 

storage/maria/ma_ft_boolean_search.c

@@ -457,7 +457,7 @@ static int _ft2_search(FTB *ftb, FTB_WORD *ftbw, my_bool init_search)
     */
     ftbw->off=off;
     ftbw->key_root= info->cur_row.lastpos;
-    ftbw->keyinfo=& info->s->ft2_keyinfo;
+    ftbw->keyinfo= info->last_key.keyinfo= & info->s->ft2_keyinfo;
     r= _ma_search_first(info, ftbw->keyinfo, ftbw->key_root);
     DBUG_ASSERT(r==0);  /* found something */
     memcpy(lastkey_buf+off, info->last_key.data,