Blender Git Loki

Cycles X: Reduce memory usage of OIDN denoiser

The idea is to perform denoising in the render buffer's
denoised pass without allocating temporary color.

This optimization covers all scenarios of when OIDN is used:
single- and multi- device rendering.

This also fixes certain artifacts caused by previous memory
optimizations which lead to a feedback loops.

Differential Revision: https://developer.blender.org/D11852