test: output tap13 instead of almost-tap

Produce a tap13-compatible output which makes it
simpler to parse. Output is still readable by
the jenkins tap plugin.

PR-URL: https://github.com/nodejs/node/pull/9262


Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Myles Borins <myles.borins@gmail.com>