Add benchmark suite

[mneumann]

To compare against ScalaJS and Dart:

https://github.com/dart-lang/benchmark_harness https://github.com/sjrd/scalajs-benchmarks

[bobzhang]

Thanks for your interest in bucklescript, our initial experiment shows it delivers excellent performance compared with hand written js, however, it's not stable enough and we would expect some low hanging fruits before the real benchmarking Contributions are very welcome, We are more than happy to help convert the bench code to idiomatic ocaml code

[bobzhang]

Ideally, we should have a CI job to monitor the performance for each commit

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.