Related: #i124856# guard against crash

Patch By: hanya
Review By: jsc

(cherry picked from commit efe87c0d84e5f76034378d48d0d1fc2025a37645)

Conflicts:
	accessibility/source/standard/vclxaccessiblebox.cxx

(cherry picked from commit 192e087f97166d2b3ff6151de04d16abbe45a1d4)

Conflicts:
	accessibility/source/standard/vclxaccessiblebox.cxx

Change-Id: I24fd4278406dacea33230cc1bf1528e3c5aaedf2
Reviewed-on: https://gerrit.libreoffice.org/10029
Tested-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Michael Stahl <mstahl@redhat.com>