unix: fix typo in test
unix: fix typo in test

Change-Id: I80b28a28a9e6133a7c8a9340ce5914498ff6bf0f
Reviewed-on: https://go-review.googlesource.com/c/sys/+/292331
Reviewed-by: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>
Trust: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/sys,golang/sys,golang/sys