Add missing extensions to binary files in order to allow execution.

Change-Id: Idfe4c72c80c26b7b938023bc7bbe1ef85e1aa7b0

Change-Id: Idfe4c72c80c26b7b938023bc7bbe1ef85e1aa7b0
GitHub-Last-Rev: ed9d8124270c30b7f25f89656432ef5089466c7e
GitHub-Pull-Request: golang/go#26464
Reviewed-on: https://go-review.googlesource.com/124936
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>