net/http: some more cookie tests
net/http: some more cookie tests

Including a commented-out test we might
tackle later, after seeing what browsers do.

R=dsymonds, rsc
CC=golang-dev
http://codereview.appspot.com/5694045

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go