benchmark: events emit

[hnry]

benchmark for events emit

tests op/count for emit for various arguments
and for single or multiple event handlers

also add the events benchmark to Makefile

[hnry]

old commit, hnry@59c8d81

separated the type into type, count
made the iteration configurable by setting it as duration
and passing lint

(side note a lot of benchmarks do not pass the included linter)

[jasnell]

@trevnorris @chrisdickinson ... do either of you see any reason to keep this open?

[jasnell]

Closing this here. Opened a new issue to track this over in nodejs/benchmarking