MDEV-18468 fixup: Make test case robust w.r.t. deferred DROP TABLE

mysql-test/suite/innodb/r/alter_varchar_change.result

@@ -460,11 +460,18 @@ DROP TABLE t1;
 DROP PROCEDURE get_index_id;
 DROP PROCEDURE get_table_id;
 create table t (a varchar(100)) engine=innodb;
-select name, pos, mtype, prtype, len from information_schema.innodb_sys_columns where name='a';
+select sc.name, sc.pos, sc.mtype, sc.prtype, sc.len
+from information_schema.innodb_sys_columns sc
+inner join information_schema.innodb_sys_tables st
+on sc.table_id=st.table_id where st.name='test/t' and sc.name='a';
 name	pos	mtype	prtype	len
 a	0	1	524303	100
 alter table t modify a varchar(110), algorithm=inplace;
-select name, pos, mtype, prtype, len from information_schema.innodb_sys_columns where name='a';
+select sc.name, sc.pos, sc.mtype, sc.prtype, sc.len
+from information_schema.innodb_sys_columns sc
+inner join information_schema.innodb_sys_tables st
+on sc.table_id=st.table_id where st.name='test/t' and sc.name='a';
 name	pos	mtype	prtype	len
 a	0	1	524303	110
 drop table t;
+# End of 10.2 tests

mysql-test/suite/innodb/t/alter_varchar_change.test

@@ -337,7 +337,15 @@ DROP PROCEDURE get_table_id;
 
 # LEN must increase here
 create table t (a varchar(100)) engine=innodb;
-select name, pos, mtype, prtype, len from information_schema.innodb_sys_columns where name='a';
+select sc.name, sc.pos, sc.mtype, sc.prtype, sc.len
+from information_schema.innodb_sys_columns sc
+inner join information_schema.innodb_sys_tables st
+on sc.table_id=st.table_id where st.name='test/t' and sc.name='a';
 alter table t modify a varchar(110), algorithm=inplace;
-select name, pos, mtype, prtype, len from information_schema.innodb_sys_columns where name='a';
+select sc.name, sc.pos, sc.mtype, sc.prtype, sc.len
+from information_schema.innodb_sys_columns sc
+inner join information_schema.innodb_sys_tables st
+on sc.table_id=st.table_id where st.name='test/t' and sc.name='a';
 drop table t;
+
+--echo # End of 10.2 tests