Goes atop MR 403 and 388. The last four commits belong to this MR.
-- v7: vkd3d-shader: Clone descriptor scan info from struct vkd3d_shader_desc. vkd3d-shader/dxil: Read CBV descriptors. vkd3d-shader/dxil: Validate the descriptor list metadata nodes. vkd3d-shader/spirv: Align constant buffer sizes to 16 bytes. vkd3d-shader/dxil: Read DXIL compute shader thread group dimensions. vkd3d-shader/dxil: Read DXIL global flags. vkd3d-shader: Define more global flags. vkd3d-shader/dxil: Handle multi-row signature elements. vkd3d-shader/dxil: Handle signature element additional tag/value pairs. vkd3d-shader/dxil: Read the DXIL input and output signatures. vkd3d-shader/dxil: Validate the entry point info.