This improves the z-combine node coverage. The tests cover the `anti_alias`, `anti_aliased_depth`, and `single_value` related functions. Coverage: - Function: 52% -> 100% - Line: 49.15% -> 98.86% - Region: 48.91% -> 96.74% - Branch: 38.46% -> 86.54% Pull Request: https://projects.blender.org/blender/blender/pulls/141071