benchmark: add test for module loader

[robertkowalski]

this adds a test for benchmarking the module loader, needed for
benchmarking changes / refacortings in the module loader.

[robertkowalski]

This comes handy for changes like #7094 and #7893

[trevnorris]

That's going to break on Windows. Instead make a tmp directory in the benchmark folder and delete it and all contents when the benchmark is complete. Then also add that to the .gitignore.

[robertkowalski]

Thanks for your input @trevnorris - tmp- folder are already git-ignored and it should work on windows now.

The benchmark-runner exits after eventually output for the console is generated: https://github.com/robertkowalski/node/blob/master/benchmark/common.js#L188-L190

So there must be some tests running without output which wait for an exit code. Extending the benchmark-runner to have a teardown-method which is run before the exit to delete the files would create wrong values for those tests.

[trevnorris]

I'm cool with this. @tjfontaine feedback?

@robertkowalski ping back if no response if a few days.

[robertkowalski]

ping

[tjfontaine]

lgtm

[trevnorris]

Thanks. Merged in efa47e5.