Fix bench subproject and make sure it builds correctly in CI.

[busti]

Running the bench subproject currently results in node-gyp throwing errors because it's version went out of sync with nodejs.
This error is only caught when running the subproject and not when compiling.

We should probably also run the benchmarks on every PR and somehow show them inside the Pull Request so that any changes don't worsen the performance of the project.

[fdietze]

The problem with those benchmarks is that they are running with jsdom and not in a browser. So the results don't have any value right now.

[busti]

Maybe we should run them using something like cypress