io.directories.search: fix linux tests.
io.directories.search: fix linux tests.

Linux doesn't return alphabetic ordering like Windows and macOS, so
we just assert the paths are iterated in the correct order by depth.

factor/factor,AlexIljin/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,bpollack/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,tgunr/factor,bpollack/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,factor/factor,tgunr/factor,AlexIljin/factor,AlexIljin/factor,AlexIljin/factor,factor/factor,bpollack/factor,AlexIljin/factor,bpollack/factor,AlexIljin/factor,AlexIljin/factor,tgunr/factor,tgunr/factor,factor/factor,bpollack/factor,bpollack/factor,factor/factor,bpollack/factor