mtr: aix test fix innodb.temporary_table

AIX error message didn't include the filename like:

2021-07-22  9:43:04 0 [ERROR] mariadbd: Can't create/write to file '' (Errcode: 20 "Not a directory")
2021-07-22  9:43:04 0 [ERROR] mariadbd: Can't create/write to file '' (Errcode: 20 "Not a directory")

Reviewer: Marko

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

@@ -11,6 +11,7 @@
 
 --disable_query_log
 call mtr.add_suppression("Can't create/write to file '/dev/null/nonexistent/ib");
+call mtr.add_suppression("Can't create/write to file '' \\\(Errcode: 20 \"Not a directory\"\\\)");
 call mtr.add_suppression("InnoDB: Unable to create temporary file");
 call mtr.add_suppression("last file in setting innodb_temp_data_file_path");
 call mtr.add_suppression("The table 't1' is full");