test_runner: fix run() none-isolation teardown hang

[inoway46]

When run({ isolation: 'none' }) is used from a cluster worker, live handles such as IPC can keep the process open after the tests finish. In that case teardown may be delayed and the run() stream can hang waiting for end.

Set an explicit teardown callback for the non-isTestRunner run() path so the stream can finalize even if the process is still being kept alive by open handles.

Add a regression test based on the reproduction from #60020.

Fixes: #60020

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.64%. Comparing base (3725bd2) to head (c8bf2a8).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62056      +/-   ##
==========================================
- Coverage   89.65%   89.64%   -0.02%     
==========================================
  Files         676      676              
  Lines      206543   206549       +6     
  Branches    39547    39548       +1     
==========================================
- Hits       185184   185155      -29     
- Misses      13480    13523      +43     
+ Partials     7879     7871       -8     

Files with missing lines	Coverage Δ
lib/internal/test_runner/runner.js	93.23% <100.00%> (+0.04%)	⬆️

... and 41 files with indirect coverage changes

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[JakobJingleheimer]

I think this might be a duplicate of #57394

[inoway46]

@JakobJingleheimer
You're right, I missed that this was already addressed in #57394. Thanks for pointing it out. I'll close this.