...which <https://ci.libreoffice.org/job/lo_tb_random_config_linux/>
occasionally stumbles across; plus some related loplugin:staticmethods fixes

Change-Id: If6998c302cfbabfcad626d9c68d94d3368548a41
Reviewed-on: https://gerrit.libreoffice.org/63808
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>