MDEV-4610 SQL query crashes MariaDB with derived_with_keys

MDEV-4643 MariaDB crashes consistently when trying a SELECT on VIEW with a UNION and an additional JOIN in SELECT

open derived temp tables *before* trying QUICK_SELECT for them,
handler::multi_range_read_info() needs an open table.

mysql-test/r/mrr_derived_crash_4610.result

+create table t1 (f1 char(4) primary key) engine=innodb charset=utf8 ;
+insert into t1 values ('aaaa');
+create table t2 (f2 text, f3 char(4) not null) engine=innodb charset=utf8 ;
+create table t3 (id int not null) engine=innodb charset=utf8 ;
+create table t4 (val int not null) engine=innodb charset=utf8;
+explain select 1 from
+(select f2, f3, val, count(id) from t4 join t2 left join t3 on 0) top
+join t1 on f1 = f3 where f3 = 'aaaa' order by val;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	const	PRIMARY	PRIMARY	12	const	1	Using index; Using filesort
+1	PRIMARY	<derived2>	ref	key0	key0	13	const	0	Using where
+2	DERIVED	t4	ALL	NULL	NULL	NULL	NULL	1	
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	1	Using join buffer (flat, BNL join)
+2	DERIVED	t3	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (incremental, BNL join)
+select 1 from
+(select f2, f3, val, count(id) from t4 join t2 left join t3 on 0) top
+join t1 on f1 = f3 where f3 = 'aaaa' order by val;
+1
+drop table t1, t2, t3, t4;

mysql-test/t/mrr_derived_crash_4610.test

+#
+# MDEV-4610 SQL query crashes MariaDB with derived_with_keys
+#
+--source include/have_innodb.inc
+create table t1 (f1 char(4) primary key) engine=innodb charset=utf8 ;
+insert into t1 values ('aaaa');
+create table t2 (f2 text, f3 char(4) not null) engine=innodb charset=utf8 ;
+create table t3 (id int not null) engine=innodb charset=utf8 ;
+create table t4 (val int not null) engine=innodb charset=utf8;
+explain select 1 from
+  (select f2, f3, val, count(id) from t4 join t2 left join t3 on 0) top
+  join t1 on f1 = f3 where f3 = 'aaaa' order by val;
+select 1 from
+  (select f2, f3, val, count(id) from t4 join t2 left join t3 on 0) top
+  join t1 on f1 = f3 where f3 = 'aaaa' order by val;
+drop table t1, t2, t3, t4;

sql/sql_select.cc

@@ -18941,6 +18941,9 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
                                              MYF(MY_WME | MY_ZEROFILL));
   table->status=0;				// May be wrong if quick_select
 
+  if (!tab->preread_init_done && tab->preread_init())
+    goto err;
+
   // If table has a range, move it to select
   if (select && !select->quick && tab->ref.key >= 0)
   {
@@ -18977,8 +18980,6 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
       get_schema_tables_result(join, PROCESSED_BY_CREATE_SORT_INDEX))
     goto err;
 
-  if (!tab->preread_init_done && tab->preread_init())
-    goto err;
   if (table->s->tmp_table)
     table->file->info(HA_STATUS_VARIABLE);	// Get record count
   table->sort.found_records=filesort(thd, table,join->sortorder, length,