gcol.innodb_virtual_purge failed in buildbot with lock wait timeout

gcol.innodb_virtual_purge 'innodb'       w3 [ fail ]

        Test ended at 2020-06-12 06:59:09

CURRENT_TEST: gcol.innodb_virtual_purge

mysqltest: At line 170: query 'TRUNCATE TABLE t2' failed: 1205: Lock wait timeout exceeded; try restarting transaction

The result from queries just before the failure was:

< snip >

CREATE TABLE t1 (a VARCHAR(30), b INT, a2 VARCHAR(30) GENERATED ALWAYS AS (a) VIRTUAL);

CREATE INDEX idx ON t1(a2(10), b, a2(20));

ERROR 42S21: Duplicate column name 'a2'

DROP TABLE t1;

#

# MDEV-17540 Server crashes in row_purge after TRUNCATE TABLE

#

CREATE TABLE t1 (a BIT(14)) ENGINE=InnoDB;

INSERT INTO t1 VALUES

(b'01110110101011'),(b'01100111111000'),(b'00001011110100'),

(b'01110110111010'),(b'10001010101011'),(b'01100111001111');

CREATE TABLE t2 (

pk INT DEFAULT 1,

b YEAR,

c BIT(14),

d YEAR AS (b),

e BIT(14) AS (c),

UNIQUE(pk),

KEY(e)

) ENGINE=InnoDB;