[fix][test] Reduce flakiness of AdminApi2Test

[lhotari]

Fixes #20376

Motivation

AdminApi2Test is extremely flaky and causes most builds to fail.

Modifications

• calling resetConfig method between test methods is the wrong solution since it creates a new instance and the running broker will keep using the old instance
  • reset properties on the existing conf instance
• use unique tenants and namespaces to make it easier to track where the possibly conflicting topics were created, if the problems preserve
• add a better solution for resetting state between test methods when it is needed
• catch exceptions in deletion and restart the cluster in the case of exceptions
  • this will handle the flakiness with resetClusters.
  • The tradeoff is that it could hide some problems that the flakiness is revealing.

Documentation

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

[lhotari]

/pulsarbot rerun-failure-checks

[eolivelli]

+1

Also this test class is very big, maybe it would be worth splitting it into smaller classes

[lhotari]

Also this test class is very big, maybe it would be worth splitting it into smaller classes

+1

[codecov-commenter]

Codecov Report

Merging #20529 (089a84b) into master (d7186a6) will decrease coverage by 0.04%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master   #20529      +/-   ##
============================================
- Coverage     72.93%   72.90%   -0.04%     
+ Complexity    31930    31820     -110     
============================================
  Files          1867     1867              
  Lines        138555   138554       -1     
  Branches      15218    15218              
============================================
- Hits         101059   101015      -44     
- Misses        29466    29522      +56     
+ Partials       8030     8017      -13     

Flag	Coverage Δ
inttests	24.20% <100.00%> (-0.04%)	⬇️
systests	24.91% <100.00%> (+0.01%)	⬆️
unittests	72.19% <100.00%> (-0.04%)	⬇️

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

Impacted Files	Coverage Δ
...rg/apache/pulsar/broker/service/BrokerService.java	80.69% <ø> (+0.14%)	⬆️
...sar/broker/service/persistent/PersistentTopic.java	79.39% <100.00%> (ø)

... and 75 files with indirect coverage changes