Merged in ruslantproductengine/viewer-neko-4cr-4 (pull request #607)

MAINT-8670 Crash in: LLFace::getGeometryVolume()

Approved-by: Andrey Lihatskiy <andreylproductengine@lindenlab.com>
Approved-by: Andrey Kleshchev <andreykproductengine@lindenlab.com>
Approved-by: Simon Linden <simon@lindenlab.com>