Remove `no-async-promise-executor` linter disables

[piranna]

Documentation of eslint no-async-promise-executor rule says:

If an async executor function throws an error, the error will be lost and won’t cause the newly-constructed Promise to reject. This could make it difficult to debug and handle some errors.

(Bold is mine)

And this is exactly what has happened to me, 16 hours catching a bug due to this :-)

This PR fix and/or replace all the places where the a Promise async executor is being defined, not only in the place where I was having problems. This way, now exceptions are not missed but instead the Promises are properly rejected when an error occurs.

The fixes in the tests that I have done to remove the eslint-disable have been:

• combine the waiting event and the method dispatching it with Promise.all()
• replace async executors for sync ones where await keyword was not being used
• swallow with void the returned Promise of an async function, that was being ignored anyway. This is not strictly necessary, but got used to it as a best practice to show the Promise is intentionally not awaited

[piranna]

I'm be off for 2 weeks and I would like to review this. Please wait until I'm back. Thanks.

Ok, thank you for notifying in advance :-)

[piranna]

Linting fixed, tests are passing.

[piranna]

Cool, thank you for merging :-)