To test: make CppunitTest_writerfilter_rtftok

These crash triggering instances were hidden by the presense of \super
in topcontext-2.rtf - so I copied it, and only removed \super.

My fix for tdf#109382 triggered a unit test failure for one
missing m_xTextFactory. It seemed safe enough to test for all of them
that aren't in try/catch blocks, not just for the specific
instance I can prove with the test.

Change-Id: I1e317e05f9bcbbb14360941ce07af1bdf0edac6a
Reviewed-on: https://gerrit.libreoffice.org/41060Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>