[VECGEOM-257] Fix division-by-zero exceptions on sphere algorithms
Branch lima/vecgeom-257 contains protections to avoid divide-by-zero operations in sphere algorithms, which have been recently reported in Geant4+VecGeom integration tests.
Branch lima/vecgeom-257 contains protections to avoid divide-by-zero operations in sphere algorithms, which have been recently reported in Geant4+VecGeom integration tests.