Bit odd to bail a unit test when reading back the document
doesn't succeed for whatever reasons.

Since there are tests that also check the initial loading
of a docx (even for ooxml export tests), leave those
untouched.

Change-Id: Iede4b360eecf3ff2c864a5d565d21120fd0e1020
Reviewed-on: https://gerrit.libreoffice.org/71503
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>