tests/sys/opencrypto: enable armv8crypto on aarch64

This change makes required modifications in runtests to also only require the
aesni module on Intel (i386/amd64) platforms, as it is an Intel specific
module.

MFC after: 1 month
MFC to: ^/stable/12 (support not present on ^/stable/11)
Submitted by: Greg V <greg@unrelenting.technology>
Differential Revision: https://reviews.freebsd.org/D21018