Blender Git Loki

Fix: Compositor test desintegrate failing on arm64

Changes introduced in commit rBe9f2f17e8518
can create different render results when there is
a Math or Mix operation after TextureOperation
on tiled execution model.
This is due to WriteBufferOperation forcing a single pixel
resolution when these operations use a preferred
resolution of 0 to check if their inputs have resolution.
Fixing this behaviour creates different renders too.

This patch keeps previous tiled implementation and
adds the new implementation only for full frame execution.

Reviewed By: Jeroen Bakker (jbakker)

Differential Revision: https://developer.blender.org/D11546