For some reason lsof is now hanging on my workstation
without the -b (avoid blocking in the kernel) option.
Adding -b makes the test pass and shouldn't hurt.
I don't know how recent the -b option is. If the builders
are ok with it, it's probably ok.
LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/166220043
Since CL 104570043 and 112720043, we are using the
nsec system call instead of /dev/bintime on Plan 9.
LGTM=rsc
R=rsc
CC=aram, golang-codereviews
https://golang.org/cl/155590043