Outputs may be re-mapped by VK_KHR_dynamic_rendering_local_read, in
which case outputs_written won't actually correspond to render targets.
Fortunately, we already have rt_written, which is properly remapped.
Reviewed-by: Lars-Ivar Hesselberg Simonsen <lars-ivar.simonsen@arm.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39274>