chore(core): set max listeners to 256 for process to avoid warnings

[raymondfeng]

Step 2 for #5011

Increase number of process listeners to avoid warnings.

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[bajtos]

I am concerned about increasing the global max-listener option. There is a good reason why Node.js reports this warning, because it's often a sign that the application has a leak. (Plus the performance of EventEmitter degrades for high number of listeners.)

Ideally, we should find a way how to fix Mocha so that it does not install so many listeners (/cc @boneskull).

If that's not possible, then let's rework this pull request to increase the global max listeners number only in our test suite.

(EDITED): The problem I see in your proposal is that it effectively disables max-listener warning for all LB4 applications.

[bajtos]

When we disable max-listener warnings in our tests, then we won't notice if our code is leaking event listeners.

IMO, we should avoid changing the global max-listener configuration at all costs and look for ways how to change max-listeners config in specific places (on specific event emitter instances) only.

[boneskull]

Which listeners do you mean?

Mocha isn’t listening for SIGINT more than once or twice. I was thinking those came out of LB (or a dep)

[boneskull]

but fwiw I wouldn’t recommend bumping it either, unless we can show that it’s not a leak and they won’t grow further

[raymondfeng]

Close to favor #5020