Add a test for Bug #28470805 DELETE CASCADE CRASHES ... ON RESTART

Thanks to commit 2614a0ab
before MDEV-5800, no version of MariaDB is affected by this bug
that was fixed in MySQL 5.7.25.

mysql-test/suite/gcol/r/innodb_virtual_fk_restart.result

@@ -7,9 +7,18 @@ CREATE TABLE t1(fld1 INT NOT NULL PRIMARY KEY) engine=innodb;
 CREATE TABLE t2(fld1 INT NOT NULL, fld2 INT NOT NULL,
 fld3 INT AS (fld2) VIRTUAL, KEY(fld1),
 FOREIGN KEY(fld1) REFERENCES t1(fld1) ON UPDATE CASCADE) engine=innodb;
+CREATE TABLE u1(a INT, KEY(a)) ENGINE=InnoDB;
+CREATE TABLE u2(b INT, vb INT GENERATED ALWAYS AS(b) VIRTUAL, KEY(vb),
+FOREIGN KEY(b) REFERENCES u1(a)ON DELETE CASCADE)ENGINE=InnoDB;
+INSERT INTO u1 SET a=1;
+INSERT INTO u2 SET b=1;
 INSERT INTO t1(fld1) VALUES(1);
 INSERT INTO t2(fld1, fld2) VALUES(1, 2);
 UPDATE t1 SET fld1= 2;
+DELETE FROM u1;
+SELECT * FROM u2;
+b	vb
+DROP TABLE u2,u1;
 SELECT fld3, fld1 FROM t2;
 fld3	fld1
 2	2

mysql-test/suite/gcol/t/innodb_virtual_fk_restart.test

@@ -11,10 +11,19 @@ CREATE TABLE t1(fld1 INT NOT NULL PRIMARY KEY) engine=innodb;
 CREATE TABLE t2(fld1 INT NOT NULL, fld2 INT NOT NULL,
 		fld3 INT AS (fld2) VIRTUAL, KEY(fld1),
 		FOREIGN KEY(fld1) REFERENCES t1(fld1) ON UPDATE CASCADE) engine=innodb;
+CREATE TABLE u1(a INT, KEY(a)) ENGINE=InnoDB;
+CREATE TABLE u2(b INT, vb INT GENERATED ALWAYS AS(b) VIRTUAL, KEY(vb),
+		FOREIGN KEY(b) REFERENCES u1(a)ON DELETE CASCADE)ENGINE=InnoDB;
+
+INSERT INTO u1 SET a=1;
+INSERT INTO u2 SET b=1;
 INSERT INTO t1(fld1) VALUES(1);
 INSERT INTO t2(fld1, fld2) VALUES(1, 2);
 --source include/restart_mysqld.inc
 UPDATE t1 SET fld1= 2;
+DELETE FROM u1;
+SELECT * FROM u2;
+DROP TABLE u2,u1;
 SELECT fld3, fld1 FROM t2;
 alter TABLE t2 ADD INDEX vk(fld3, fld1), ALGORITHM=INPLACE;
 UPDATE t1 SET fld1=3;