[fix][test] Fix more resource leaks in tests

[lhotari]

Motivation

Fixing Netty ByteBuf leaks in test code is needed for executing the plan explained in Enhancing Pulsar CI with Netty leak detection and reporting. The Pulsar CI Netty leak detection and reporting solution was added in #24272.

Modifications

• Fix thread leaks in these tests:
  • ProxySaslAuthenticationTest (indent was also changed from tabs to spaces)
  • BookieRackAffinityMappingTest
  • RateLimiterTest
  • FileSystemOffloaderLocalFileTest
  • Fix thread leaks in tests using BookKeeperClusterTestCase base class
• Fix ByteBuf leaks in these tests
  • FileSystemManagedLedgerOffloaderTest

Documentation

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

Matching PR in forked repository

PR in forked repository:

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

Project coverage is 74.33%. Comparing base (bbc6224) to head (243f1ed).
Report is 1104 commits behind head on master.

Files with missing lines	Patch %	Lines
...kkeeper/mledger/impl/ManagedLedgerFactoryImpl.java	75.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #24314      +/-   ##
============================================
+ Coverage     73.57%   74.33%   +0.75%     
+ Complexity    32624    32280     -344     
============================================
  Files          1877     1866      -11     
  Lines        139502   145101    +5599     
  Branches      15299    16591    +1292     
============================================
+ Hits         102638   107859    +5221     
+ Misses        28908    28722     -186     
- Partials       7956     8520     +564     

Flag	Coverage Δ
inttests	26.80% <12.50%> (+2.21%)	⬆️
systests	23.35% <0.00%> (-0.98%)	⬇️
unittests	73.81% <77.77%> (+0.97%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...filesystem/impl/FileStoreBackedReadHandleImpl.java	62.24% <100.00%> (+5.77%)	⬆️
...kkeeper/mledger/impl/ManagedLedgerFactoryImpl.java	59.55% <75.00%> (-21.84%)	⬇️

... and 1088 files with indirect coverage changes

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[lhotari]

skipping cherry-picking to branch-3.0 since this change depends on #21425, which isn't included in branch-3.0.