Test cleanup, the upgrade test script assumes a unix like environment

mysql-test/t/upgrade.test:
  Test cleanup, --exec mkdir does not work on windows platforms

mysql-test/t/upgrade.test

 -- source include/not_embedded.inc
 
+# Temporary disabled on windows,
+# because of --exec mkdir
+# TODO: implement Bug#31004 and remove this limitation
+--source include/not_windows.inc
+
 --disable_warnings
 drop database if exists `mysqltest1`;
 drop database if exists `mysqltest-1`;
@@ -60,7 +65,6 @@ drop table t1;
 # Bug#28360 (RENAME DATABASE destroys routines)
 #
 
-
 --disable_warnings
 drop database if exists `tabc`;
 drop database if exists `a-b-c`;