This is for filling a column with "fail", like I just did for
Windows, when the builder would get stuck running that
build. (We have safeguards against the tests getting stuck
but this was the bootstrap build getting stuck.)
I usually use -cmd=/bin/false, but this avoids the Mercurial
checkouts, which means it runs instantly instead of requiring
~1 minute per "fail".
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/5649049
ee3e24f2d7