Cleanup and simplification of GPUMaterial and GPUPass compilation.
See #133674 for details/goals.
- Remove the `draw_manage_shader` thread.
Deferred compilation is now handled by the gpu::ShaderCompiler
through the batch compilation API.
Batch management is handled by the `GPUPassCache`.
- Simplify `GPUMaterial` status tracking so it just queries the
`GPUPass` status.
- Split the `GPUPass` and the `GPUCodegen` code.
- Replaced the (broken) `GPU_material_recalc_flag_get` with the new
`GPU_pass_compilation_timestamp`.
- Add the `GPU_pass_cache_wait_for_all` and
`GPU_shader_batch_wait_for_all`, and remove the busy waits from
EEVEE.
- Remove many unused functions, properties, includes...
Pull Request: https://projects.blender.org/blender/blender/pulls/135637
e6638d6e5e