s390x: stsi: Make output tap13 compatible

In tap13 output # is a special character and only "skip" and "todo"
are allowed to come after it. Let's appease our CI environment and
replace # with "count".

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20200525084340.1454-1-frankja@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>