Currently we keep track of 3 command buffers. Data transfer, compute and
graphics. The reason is that data transfer and compute commands cannot
be recorded in a command buffer that has an active render pass.
This PR simplifies the implementation by combining data transfer and
compute commands as there is no need to separate those in individual
command buffers.
This is in preparation of improving submission performance.
Pull Request: https://projects.blender.org/blender/blender/pulls/115033
54e1ee3905