Coverage in aegir + node hangs on CI and Local Dev

[laurentsenta]

Describe the bug

We had to disable code coverage in node 18, which pushed the burden of checking code coverage onto maintainers and PR reviewers.

@achingbrain has prepared a PR to enable it back, but it's still blocking:
#1195

Examples:
https://github.com/ipfs/aegir/actions/runs/4225847659/jobs/7338650113

@BigLep shared details on why we need to solve this in https://filecoinproject.slack.com/archives/C03KLC57LKB/p1678122004165499

Options:

• Figure out what happens and fix it,
• Use a different code coverage tool that doesn't have the same issue.
  • NYC might be abandoned: Is this repository deprecated/abandoned? istanbuljs/nyc#1514

[laurentsenta]

Issue was created in bcoe/c8#454

There is a nodejs related issue discussed in bcoe/c8#432, which leads to nodejs/node#45013 and nodejs/node#45055.

Naively, I tried to run the test on many different version, hoping I would find a clear "v18 is broken" or something.
But, if you exclude the "missing fetch function" on older nodejs versions, it seems that every version hangs, except the node v19 on windows:
https://github.com/laurentsenta/aegir/actions/runs/4353486483/jobs/7607591085

[RonaldZielaznicki]

According to this comment (bcoe/c8#432 (comment)), folks are able to fix the issue by moving to node v20.

[achingbrain]

I've updated the PR that re-enables coverage to only run coverage on node 20 but it still hangs so I think that comment is a red herring.

Edit: Actually looking at that issue they're reporting a segfault which is not the problem we are seeing. The problem we see is detailed above - the process hangs after the test run finishes, it doesn't crash.

[achingbrain]

Possibly related: nodejs/node#49344