runtime/race: add end-to-end test on windows
runtime/race: add end-to-end test on windows

whatever "end-to-end" means here

R=golang-dev, dvyukov
CC=golang-dev
https://codereview.appspot.com/12898044

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang