fdo#70345 Reuse XStream for Windows platform create a new one for others.

Change-Id: I911c24b82b55445c6f95e14be29759e2fe3d9dfd
Reviewed-on: https://gerrit.libreoffice.org/6580
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>