don't crash if demangling fails, fdo#52539
don't crash if demangling fails, fdo#52539

project-zerus/cppunit,project-zerus/cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,ryancalhoun/cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,LesleyLai/cppunit,ryancalhoun/cppunit,ryancalhoun/cppunit,LesleyLai/cppunit,project-zerus/cppunit,ryancalhoun/cppunit,freedesktop-unofficial-mirror/libreoffice__cppunit,LesleyLai/cppunit,LesleyLai/cppunit