update test

tests/queries/0_stateless/01821_table_comment.reference

@@ -1,3 +1,4 @@
 t1	this is a temtorary table
 t2	this is a MergeTree table
 t3	this is a Log table
+CREATE TABLE default.t1\n(\n    `n` Int8\n)\nENGINE = Memory\nCOMMENT \'this is a temtorary table\'

tests/queries/0_stateless/01821_table_comment.sql

@@ -30,6 +30,8 @@ SELECT
 FROM system.tables
 WHERE name IN ('t1', 't2', 't3') order by name;
 
+SHOW CREATE TABLE t1;
+
 DROP TABLE t1;
 DROP TABLE t2;
 DROP TABLE t3;