MDEV-29021 add test case from MDEV-29013

This test case was also fixed by adding update_virtual_columns.

mysql-test/main/alter_table_online_debug.result

@@ -650,7 +650,7 @@ set debug_sync= reset;
 #
 # MDEV-29021 ALTER TABLE fails when a stored virtual column is dropped and added
 #
-create table t1 (a char(9), b char(9) as (a) stored) engine=InnoDB;
+create table t1 (a char(9), b char(9) as (a) stored);
 insert into t1(a) values ('foobar');
 set debug_sync= 'now wait_for downgraded';
 connection con2;
@@ -708,6 +708,24 @@ connection default;
 drop table t1;
 set debug_sync= reset;
 #
+# DELETE with added virtual column
+#
+CREATE TABLE t1 (a CHAR(3), b CHAR(3) AS (a));
+INSERT INTO t1 (a) VALUES ('foo'),('bar');
+set debug_sync= 'now wait_for downgraded';
+connection con2;
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+ALTER TABLE t1 ADD c INT, ALGORITHM=COPY, LOCK=NONE;
+connection default;
+DELETE FROM t1;
+set debug_sync= 'now signal goforit';
+connection con2;
+select * from t1;
+a	b	c
+connection default;
+DROP TABLE t1;
+set debug_sync= reset;
+#
 # Do not ignore sql_mode when replicating
 #
 create table t1 (a int);

mysql-test/main/alter_table_online_debug.test

@@ -804,7 +804,7 @@ set debug_sync= reset;
 --echo #
 --echo # MDEV-29021 ALTER TABLE fails when a stored virtual column is dropped and added
 --echo #
-create table t1 (a char(9), b char(9) as (a) stored) engine=InnoDB;
+create table t1 (a char(9), b char(9) as (a) stored);
 insert into t1(a) values ('foobar');
 
 --send set debug_sync= 'now wait_for downgraded'
@@ -875,6 +875,32 @@ show create table t1;
 drop table t1;
 set debug_sync= reset;
 
+--echo #
+--echo # DELETE with added virtual column
+--echo #
+CREATE TABLE t1 (a CHAR(3), b CHAR(3) AS (a));
+INSERT INTO t1 (a) VALUES ('foo'),('bar');
+--send
+set debug_sync= 'now wait_for downgraded';
+
+--connection con2
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+--send
+ALTER TABLE t1 ADD c INT, ALGORITHM=COPY, LOCK=NONE;
+
+--connection default
+--reap
+DELETE FROM t1;
+set debug_sync= 'now signal goforit';
+
+--connection con2
+--reap
+select * from t1;
+
+--connection default
+DROP TABLE t1;
+set debug_sync= reset;
+
 --echo #
 --echo # Do not ignore sql_mode when replicating
 --echo #