test: improve internet/test-dns

* change 'for' loop to 'for of' loop
* remove unused parameters passed to functions
* remove unnecessary 'assert.ok'

PR-URL: https://github.com/nodejs/node/pull/24927


Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>