test: fix flaky test-benchmark-events

Make sure each benchmark file only runs one combination of options.
Allow for zero iterations for short benchmark.

PR-URL: https://github.com/nodejs/node/pull/17472


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>