build: support dtrace on ARM

Use the same dtrace command on ARM as on i386. Patch obtained from
FreeBSD PR 218081 [1].

1. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=218081

PR-URL: https://github.com/nodejs/node/pull/12193


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>