[MDEV-30002] Skip bad_startup_options test when running as root (#2344)

Commit 32158be added a new test `bad_startup_options`. This test fails
if run as root, which is common on many CI systems.

This test should include `not_as_root.inc` so it is skipped, just
like all other similar tests in MariaDB.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer
Amazon Web Services, Inc.

mysql-test/main/bad_startup_options.test

@@ -1,3 +1,6 @@
+# mysqld refuses to run as root normally.
+--source include/not_as_root.inc
+
 --source include/not_embedded.inc
 --source include/have_ssl_communication.inc