net: add deadline prolongation test Currently the test exposes data races on deadline vars.
net: add deadline prolongation test
Currently the test exposes data races on deadline vars.

R=golang-dev, dave, bradfitz, rsc
CC=golang-dev
http://codereview.appspot.com/6845091

pombredanne/go-deleteme,dsriram/golang,apparentlymart/golang,gnanderson/go,dsriram/golang,apparentlymart/golang,apparentlymart/golang,gnanderson/go,pombredanne/go-deleteme,pombredanne/go-deleteme,dsriram/golang,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,gnanderson/go,gnanderson/go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,gnanderson/go,gnanderson/go,tv42/old-go,apparentlymart/golang,gnanderson/go,dsriram/golang,dsriram/golang,apparentlymart/golang,dsriram/golang,apparentlymart/golang,apparentlymart/golang,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,tv42/old-go