cluster: report EADDRINUSE when a worker listens twice on the same port

[islandryu]

Fixes: #64869

Prevent an assertion error in child.js when a worker attempts to listen twice on the same port by detecting duplicate handle registrations in the primary process.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.14%. Comparing base (facd71e) to head (d095f6e).
⚠️ Report is 1257 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65020      +/-   ##
==========================================
+ Coverage   90.04%   90.14%   +0.10%     
==========================================
  Files         713      751      +38     
  Lines      224950   252648   +27698     
  Branches    42530    47542    +5012     
==========================================
+ Hits       202548   227754   +25206     
- Misses      14188    16182    +1994     
- Partials     8214     8712     +498     

Files with missing lines	Coverage Δ
lib/internal/cluster/primary.js	94.75% <100.00%> (+0.14%)	⬆️

... and 461 files with indirect coverage changes

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[PickBas]

I have a suggestion for the test: it passes on an unpatched build under SCHED_RR (the POSIX default), so it wouldn't catch a regression on Linux/macOS. The PR fixes behavior with SCHED_NONE, so could the tests cover both SCHED_RR and SCHED_NONE policies regardless of the OS?

[islandryu]

Good catch! I've covered both policies.