process: improve rejections tracking performance

[mmarchini]

Fixes: https://github.com/nodejs/node/issues/34851

Before landing

• [ ] Explain why this works on commit message
• [ ] Add comments to the code to explain what's going on

Checklist

• [x] make -j4 test (UNIX), or vcbuild test (Windows) passes
• [ ] tests and/or benchmarks are included
• [ ] documentation is changed or added
• [x] commit message follows commit guidelines

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/32877/

[mmarchini]

Test failures look legit, but I can't reproduce locally

[matt4530]

Just following up on this since it looks like the CI process got fixed (or at least it is no longer reporting). Can we re-run the CI to see if your patch passes?

[Uzlopak]

@H4ad

We can close this PR now ;)