QuatExpMap: Use some ApproxQuat to hopefully fix tests.
QuatExpMap: Use some ApproxQuat to hopefully fix tests.

Wasn't needed on Buster, but might be needed on VS2019.

OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core