net: fix incorrect internal IPv6 address representation in test
net: fix incorrect internal IPv6 address representation in test

Also fixes a dialgoogle test glitch after issue 6628 fix.

R=golang-codereviews, r
CC=golang-codereviews
https://codereview.appspot.com/50660044

apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang