[fix][test] Fix flaky test PulsarMultiListenersWithoutInternalListenerNameTest.setup

[lhotari]

Fixes #19005

Motivation

See #19005

Modifications

Change free port allocation so that both ports are detected at once. Use SO_REUSEADDR socket option for PortForwarder.

• doc
• doc-required
• doc-not-needed
• doc-complete

[github-actions]

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 46.49%. Comparing base (22866bd) to head (49667e6).
Report is 1933 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #19006      +/-   ##
============================================
+ Coverage     45.92%   46.49%   +0.57%     
- Complexity    10104    10473     +369     
============================================
  Files           680      706      +26     
  Lines         66758    69004    +2246     
  Branches       7147     7392     +245     
============================================
+ Hits          30660    32085    +1425     
- Misses        32680    33321     +641     
- Partials       3418     3598     +180     

Flag	Coverage Δ
unittests	46.49% <ø> (+0.57%)	⬆️

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see 64 files with indirect coverage changes