test: exercise once() with varying arguments

This commit regains test coverage for EventEmitter#once() with
four or more arguments. To avoid similar regressions in the
future, once() is called with enough arguments to cover all of
the separate code paths.

PR-URL: https://github.com/nodejs/node/pull/13524


Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>