test: refactor test-stdin-from-file

Remove console.log statement. Replace error check with
assert.ifError().

PR-URL: https://github.com/nodejs/node/pull/10331


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>