bugfix: the issue of possible infinite loop when cleaning up expired metadata info

[funky-eyes]

What is the purpose of the change?

fix #15087

Checklist

• Make sure there is a GitHub_issue field for the change.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test to verify your logic correction. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 94.44444% with 1 line in your changes missing coverage. Please review.

Project coverage is 60.75%. Comparing base (bda147a) to head (fc5a58b).
Report is 138 commits behind head on 3.3.

Files with missing lines	Patch %	Lines
...ubbo/registry/client/AbstractServiceDiscovery.java	94.44%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                3.3   #15086      +/-   ##
============================================
+ Coverage     60.73%   60.75%   +0.01%     
- Complexity    10864    10872       +8     
============================================
  Files          1882     1882              
  Lines         86009    86009              
  Branches      12886    12887       +1     
============================================
+ Hits          52239    52254      +15     
+ Misses        28322    28311      -11     
+ Partials       5448     5444       -4     

Flag	Coverage Δ
integration-tests	33.06% <16.66%> (+0.03%)	⬆️
samples-tests	29.23% <16.66%> (+0.01%)	⬆️
unit-tests	58.88% <94.44%> (-0.01%)	⬇️

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[finefuture]

LGTM.

[chickenlj]

LGTM.