StdPrs_ToolShadedShape::IsClosed():
- return true if shape is closed Solid (NOT just free closed Shell)
- accept compound of closed Solids as well
- ignore Solids with incomplete triangulation
TKOpenGl, automatically disable back face culling when:
- clipping/capping planes are in effect
- for translucent objects
Update bug23227 test case (now back faces are clipped).
OpenGl_Workspace::AspectFace() - disable culling in case of hatched style