They are no longer used outside the package since CL 38080.

Passes toolstash-check -all

Change-Id: I30977ed2b233b7c8c53632cc420938bc3b0e37c6
Reviewed-on: https://go-review.googlesource.com/129781
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>