instead of bittwiddling which ends up trying to resolve the
system language

(cherry picked from commit a1ff0745)

more tdf#76964 fall back to primary language via getLanguage

(cherry picked from commit 97893e56)

sw: fix SwUiWriterTest pointlessly loading an "empty.odt" ...

... instead of just creating a new document.

(cherry picked from commit 98ddd7a3)

Change-Id: I545bd5e39f99003ddedf3c90031e8b818edc1de2
Reviewed-on: https://gerrit.libreoffice.org/19545Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>