follow-up commit to https://gerrit.libreoffice.org/#/c/9226/ .
text_cat -s was documented as "Not very efficient yet, because
language models are re-loaded after each line." So if we want
to use text_cat -s for thousands of lines, better
read the language models only once and store them.
When tested on svl/source, the speed-up was a futher factor 1.5
(reduced from 6 s to 4 s).
Reviewed-on: https://gerrit.libreoffice.org/9227Reviewed-by: Michael Meeks <firstname.lastname@example.org>
Tested-by: Michael Meeks <email@example.com>