It's disabled for now. We need to first make the edit engine and
a few other places thread-safe before we can parallelize this code.

Change-Id: Ie09536964ece42d43f505afc5e2611d469cc5c95
Reviewed-on: https://gerrit.libreoffice.org/38424Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>