It's allowed to compress different page streams differently, and we must
have a single object stream for our form XObject, so just incompress all
of them to be consistent.

Change-Id: I7a20dc2084a902a37dcefa3420d59a576f120bcd
Reviewed-on: https://gerrit.libreoffice.org/36409Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>