Blender Git Loki

Cycles: Change device-only memory to actually only allocate on the device

This patch changes the `MEM_DEVICE_ONLY` type to only allocate on the device and fail if
that is not possible anymore because out-of-memory (since OptiX acceleration structures may
not be allocated in host memory). It also fixes high peak memory usage during OptiX
acceleration structure building.

Reviewed By: brecht

Maniphest Tasks: T85985

Differential Revision: https://developer.blender.org/D10535