optimize AbstractConfigTest

[Linchen-Xu]

What is the purpose of the change

optimize AbstractConfigTest

Brief changelog

org.apache.dubbo.config.AbstractConfigTest

• Rewrite testAppendProperties related tests because AbstractConfig.appendProperties no longer exists.
• Remove unused inner test class PropertiesConfig.

Verifying this change

Checklist

• Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• Each commit in the pull request should have a meaningful subject line and body.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Check if is necessary to patch to Dubbo 3 if you are work on Dubbo 2.7
• Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Add some description to dubbo-website project if you are requesting to add a feature.
• GitHub Actions works fine on your own branch.
• If this contribution is large, please follow the Software Donation Guide.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[codecov-commenter]

Codecov Report

Merging #13243 (943caf5) into 3.2 (be15772) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                3.2   #13243      +/-   ##
============================================
- Coverage     69.51%   69.50%   -0.02%     
  Complexity        2        2              
============================================
  Files          1653     1653              
  Lines         68937    68937              
  Branches      10045    10045              
============================================
- Hits          47919    47912       -7     
- Misses        16387    16389       +2     
- Partials       4631     4636       +5     

see 27 files with indirect coverage changes

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