MDEV-21842 auto_increment does not increment with compound primary key on partitioned table.

The idea of this fix is that it's enough to prevent the
next_auto_inc_val from incrementing if an error, to fix this problem
and also the MDEV-17333.
So this patch basically reverts the existing fix to the MDEV-17333.

mysql-test/main/auto_increment_ranges_innodb.test

@@ -18,3 +18,62 @@ select * from t1;
 drop table t1;
 --let $datadir=`select @@datadir`
 --remove_file $datadir/test/load.data
+
+--echo #
+--echo # MDEV-21842: auto_increment does not increment with compound primary
+--echo # key on partitioned table
+--echo #
+
+create or replace table `t` (
+  `id` bigint(20) unsigned not null auto_increment,
+  `a` int(10) not null ,
+  `dt` date not null,
+  primary key (`id`, `dt`) ,
+  unique key (`a`, `dt`)
+)
+ partition by range  columns(`dt`)
+(
+ partition `p202002` values less than ('2020-03-01'),
+ partition `P202003` values less than ('2020-04-01')
+);
+
+connect (con1, localhost, root,,);
+connect (con2, localhost, root,,);
+
+--connection con1
+start transaction;
+insert into t (a, dt) values (1, '2020-02-29');
+
+--connection con2
+start transaction;
+let $conn2_id= `SELECT CONNECTION_ID()`;
+send insert into t (a, dt) values (1, '2020-02-29');
+
+--connection con1
+# Ensure that the above insert via conn2 increments next_auto_inc_val
+# before the following insert via conn1 starts.
+let $wait_condition=select 1 from Information_schema.INNODB_TRX
+    where trx_mysql_thread_id = $conn2_id and trx_state = 'LOCK WAIT'
+    and trx_query = "insert into t (a, dt) values (1, '2020-02-29')";
+--source include/wait_condition.inc
+
+insert into t (a, dt) values (2, '2020-02-29');
+select auto_increment from information_schema.tables where table_name='t';
+commit;
+
+--connection con2
+--error ER_DUP_ENTRY
+reap;
+
+--connection con1
+select auto_increment from information_schema.tables where table_name='t';
+insert into t (a, dt) values (3, '2020-02-29');
+insert into t (a, dt) values (4, '2020-02-29');
+
+disconnect con1;
+disconnect con2;
+
+--connection default
+select * from t;
+drop table t;
+