Closed requested to merge alyssa/mesa:panfrost/tiler-for-u_blitter into main
u_blitter allows drivers to implement their own draw_rectangle path, using hardware-specific features to accelerate simple 2D blits beyond what draw_vbo can do. In particular, draw_rectangle provides access to the vertex attributes and does not mandate the use of a vertex shader. This commit implements draw_rectangle using the infrastructure in pan_blit, generating a tiler job directly, avoiding the roundtrip through a vertex shader.
Draft because I hate this whole series so much. The goal was investigating what we'll want on the panvk side for !17438