tu: Fix empty blit scissor case

With vertexPipelineStoresAndAtomics enabled, fixes:
dEQP-VK.tessellation.invariance.one_minus_tess_coord_component.quads_fractional_even_spacing_cw_point_mode
dEQP-VK.tessellation.invariance.tess_coord_component_range.triangles_fractional_even_spacing_ccw_point_mode

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5738>
1 file changed