test: refactor event-emitter-check-listener-leaks

* add block-scoping
* use common.mustCall() on callbacks that should not execute

PR-URL: https://github.com/nodejs/node/pull/13164


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>