Move this to struct ImplSVWinData, which is deleted on shutdown.

Change-Id: Ie604c2105f1176858b4050fb34d37cf376f8f82a
Reviewed-on: https://gerrit.libreoffice.org/42631Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>