Add CI that automatically runs benchmarks and posts them to the PR

[Robbepop]

After https://github.com/paritytech/wasmi/issues/304 has been implemented it would be nice to have benchmarks run automatically for every PR and PR update similar to how it is already done with test coverage reporting via codecov.io.

I personally do not know what needs to be done with GitHub Actions CI or if that's actually feasible without a ton of work.

[Robbepop]

I found this GitHub Actions and will try to make it work for wasmi.

[Robbepop]

My personal summary is that https://github.com/marketplace/actions/criterion-compare-prs is not a fit to close the linked issue since the GitHub Actions unfortunately is heavily outdated and has outdated documentation which is a red flag anyways.

We need to look for another solution or build our own GitHub Actions for comparing Citerion benchmarks.

Closed.

[Robbepop]

Did not want to close this issue but the linked PR: https://github.com/paritytech/wasmi/pull/324

[Robbepop]

Maybe running Criterion benchmarks on GitHub Actions CI is too noisy. The well known Cachegrind tool is made exactly for usage scenarios like these. The experimental (unreleased) lai tool from the same author as Criterion might help here.

[Robbepop]

This is being worked on by @sergejparity here https://github.com/paritytech/wasmi/pull/422.

[Robbepop]

Implemented in https://github.com/paritytech/wasmi/pull/422. Closed.