I noticed that they were unimplemented on arm64 but then that they were
in fact not used at all.

Change-Id: Iee579feda2a5e374fa571bcc8c89e4ef607d50f6
Reviewed-on: https://go-review.googlesource.com/13951
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>