Support for the AO and bevel shader nodes requires calling "optixTrace" from within the shading VM, which is only allowed from inlined functions to the raygen program or callables. This patch therefore converts the shading VM to use direct callables to make it work. To prevent performance regressions a separate kernel module is compiled and used for this purpose. Reviewed By: brecht Differential Revision: https://developer.blender.org/D9733