[fix][test] Fix flaky test AdditionalServletsTest.testEmptyStringAsExtractionDirectory

[andrasbeni]

Fixes #18587

Motivation

AdditionalServletsTest.testEmptyStringAsExtractionDirectory is flaky because it depends on NarClassLoader#DEFAULT_NAR_EXTRACTION_DIR being initialized after the test is begun.

Modifications

Remove the override of the tmp directory from the test.

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

• This change only modifies test code

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• Anything that affects deployment

Documentation

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

Matching PR in forked repository

PR in forked repository: andrasbeni#8

[lhotari]

/pulsarbot rerun-failure-checks

[codecov-commenter]

Codecov Report

Merging #18607 (6e37bda) into master (598ca5d) will decrease coverage by 6.08%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master   #18607      +/-   ##
============================================
- Coverage     47.72%   41.63%   -6.09%     
+ Complexity     9330     2407    -6923     
============================================
  Files           618      235     -383     
  Lines         58568    16666   -41902     
  Branches       6093     1818    -4275     
============================================
- Hits          27951     6939   -21012     
+ Misses        27589     8968   -18621     
+ Partials       3028      759    -2269     

Flag	Coverage Δ
unittests	41.63% <ø> (-6.09%)	⬇️

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

Impacted Files	Coverage Δ
.../org/apache/pulsar/client/impl/ConnectionPool.java	37.43% <0.00%> (-1.03%)	⬇️
...a/org/apache/pulsar/client/impl/TableViewImpl.java	0.00% <0.00%> (ø)
...pache/pulsar/client/impl/TableViewBuilderImpl.java	0.00% <0.00%> (ø)
...pache/pulsar/broker/admin/v2/PersistentTopics.java
...org/apache/pulsar/broker/service/Subscription.java
.../broker/intercept/BrokerInterceptorDefinition.java
...rg/apache/pulsar/broker/web/PulsarWebResource.java
...ava/org/apache/pulsar/broker/stats/TimeWindow.java
...g/apache/pulsar/broker/service/StreamingStats.java
...g/TopicCountEquallyDivideBundleSplitAlgorithm.java
... and 383 more