net: fix windows and plan9 build

Don't call unix-only function in test init.

R=golang-dev, alex.brainman
CC=golang-dev
https://codereview.appspot.com/7778043
unicode/utf8: fix insignificant typos in tests

Fixes issue 4972.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/7649044

Committer: Brad Fitzpatrick <bradfitz@golang.org>