This adds use* flags for all arches so a common test can observe what implementations are supported and test all supported implementations. Change-Id: I0497b91294ed99309074ac4614ac996e006630c5 Reviewed-on: https://go-review.googlesource.com/31714 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Andreas Auernhammer <aead@mail.de>