f7e4fbc636
This removes the use of `system_gpu_context_mutex` which was making render command submission threadsafe. The only issue is the concurent usage of GPUShader objects. To fix this, we only guard the submission section which are the only parts that uses the GPUShaders. Removing this critical section all together requires some changes in the GPUShader. See #135406 Rel #134690 Pull Request: https://projects.blender.org/blender/blender/pulls/135595