Skip open_de9b3fb438 s390x to avoid OOM

Skip open_de9b3fb438 s390x to avoid OOM

Forwarded: no
X-Not-Forwarded-Reason: Unclear where/how exactly
Origin: <todo-URL-to-git or similar>
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/freecad/+bug/1918474
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=984952
Last-Update: 2021-03-15

The load of the current file in test_open_head is fine, but
open_de9b3fb438 goes into an OOM even in huge (e.g. 10GB) systemd.
This probably needs a proper fix by upstream in regard to the migration
modules that load the old code, but until then (since the rest works on s390x)
this unblocks the package self-test in Debian & Ubuntu.

Gbp-Pq: Name fix-s390x-test-fail-skip-load-old-file.patch