events: fix weak listener retention overwrite

[aryansaves]

The weakListeners() retention map in EventTarget stored a single listener per retainer key. Multiple addEventListener() calls sharing the same retainer (e.g. two listeners on one target using the same AbortSignal) silently evicted each other's strong reference, allowing the evicted listener to be garbage collected before its signal aborted, so only the most recently registered listener was ever actually removed on abort.

Changed the retention map to store a Set of listeners per retainer key instead of a single listener, and added matching cleanup in remove() so entries are released once their retainer's set is empty.

This also fixes the same class of bug in events.aborted() and the streams kWeakHandler usage, since both go through the same EventTarget.prototype.addEventListener() code path.

Fixes: #63954

[aryansaves]

Friendly ping, could a collaborator approve CI when there's a moment , happy to address any review feedback.

[aryansaves]

CI workflows are still awaiting approval, could someone approve the workflow run when there's a moment?

[aryansaves]

CI ran but two jobs failed (node-test-commit, node-test-pull-request) I don't have Jenkins read access to check the logs, could a collaborator check ?

[trivikr]

@aryansaves Can you please rebase?

Flaky tests are failing in test-build-sea which would have been either marked as flaky or fixed in recent commits.

[aryansaves]

@trivikr rebase done, CI needs approval

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/76475/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.13%. Comparing base (4b5e86c) to head (225349a).
⚠️ Report is 14 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64024      +/-   ##
==========================================
- Coverage   90.14%   90.13%   -0.01%     
==========================================
  Files         751      751              
  Lines      253679   253700      +21     
  Branches    47789    47800      +11     
==========================================
+ Hits       228671   228684      +13     
- Misses      16264    16272       +8     
  Partials     8744     8744              

Files with missing lines	Coverage Δ
lib/internal/event_target.js	98.80% <100.00%> (+0.02%)	⬆️

... and 31 files with indirect coverage changes

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