Fix order-sensitive thread pool status test

[yuzhiyang1]

What changed

• Updated ThreadPoolStatusCheckerTest to assert pool status entries independently instead of relying on DataStore map iteration order.
• Added cleanup in a finally block so executors and DataStore entries are reset even if an assertion fails.

Why

NonDex can shuffle the internal map iteration order, which makes the previous full-message equality assertion flaky even though the checker result is semantically correct.

Fixes #16152

Validation

• .\mvnw.cmd test -pl dubbo-rpc/dubbo-rpc-dubbo '-Dtest=org.apache.dubbo.rpc.protocol.dubbo.status.ThreadPoolStatusCheckerTest#test' '-Dcheckstyle.skip=true' '-Drat.skip=true'
• .\mvnw.cmd edu.illinois:nondex-maven-plugin:2.2.1:nondex -pl dubbo-rpc/dubbo-rpc-dubbo '-Dtest=org.apache.dubbo.rpc.protocol.dubbo.status.ThreadPoolStatusCheckerTest#test' -DnondexRuns=10

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 60.79%. Comparing base (b65573e) to head (f76451e).

Additional details and impacted files

@@             Coverage Diff              @@
##                3.3   #16300      +/-   ##
============================================
- Coverage     60.80%   60.79%   -0.02%     
+ Complexity    11766    11765       -1     
============================================
  Files          1953     1953              
  Lines         89188    89188              
  Branches      13454    13454              
============================================
- Hits          54235    54223      -12     
- Misses        29391    29399       +8     
- Partials       5562     5566       +4     

Flag	Coverage Δ
integration-tests-java21	32.16% <ø> (+0.03%)	⬆️
integration-tests-java8	32.24% <ø> (+<0.01%)	⬆️
samples-tests-java21	32.12% <ø> (-0.07%)	⬇️
samples-tests-java8	29.85% <ø> (-0.02%)	⬇️
unit-tests-java11	59.02% <ø> (-0.03%)	⬇️
unit-tests-java17	58.49% <ø> (-0.04%)	⬇️
unit-tests-java21	58.49% <ø> (+<0.01%)	⬆️
unit-tests-java25	58.46% <ø> (-0.02%)	⬇️
unit-tests-java8	59.01% <ø> (+<0.01%)	⬆️

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[zrlw]

Hope this one will be approved by two committers,
#16153 and #16154 did the same thing.

[zrlw]

LGTM