Fix: Stabilize URLParam.hashCode() to prevent Non-Dex nondeterminism in URLTest.testHashcode

[Anshul-creator]

What is the purpose of the change?

This PR stabilizes URLParam.hashCode() to eliminate Non-Dex flakiness in tests (notably URLTest.hashCode).

Root Cause

The previous implementation multiplied hashCodeCache by 31 for each map entry.
Because iteration order over EXTRA_PARAMS (a HashMap) is nondeterministic, the resulting hash code varied between runs, breaking consistency with equals() and causing nondeterministic test failures.

Changes Made

• Replaced the order-dependent multiplication-based accumulation with an order-independent summation of entry.hashCode() values.
• Kept the same handling for VALUE, KEY, and ignored TIMESTAMP_KEY.
• Preserved the existing structure and caching logic.

Verification

You can try running the following snippet of code from the dubbo repo root, on both pre-fix and post-fix code

./mvnw -pl dubbo-common edu.illinois:nondex-maven-plugin:2.2.1:nondex \
  -DnondexRuns=20 \
  -Dtest=org.apache.dubbo.common.URLTest#testHashcode

The test should fail intermittently on the pre-fix version, but pass consistently across all seeds on the post-fix version.
NonDex run logs will be available under the dubbo-common/.nondex directory.

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

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 60.77%. Comparing base (3720471) to head (9d3bcc2).

Files with missing lines	Patch %	Lines
...rg/apache/dubbo/common/url/component/URLParam.java	80.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##                3.3   #15757   +/-   ##
=========================================
  Coverage     60.76%   60.77%           
- Complexity    11727    11728    +1     
=========================================
  Files          1938     1938           
  Lines         88637    88638    +1     
  Branches      13380    13379    -1     
=========================================
+ Hits          53864    53867    +3     
- Misses        29245    29246    +1     
+ Partials       5528     5525    -3     

Flag	Coverage Δ
integration-tests-java21	32.38% <80.00%> (+0.05%)	⬆️
integration-tests-java8	32.40% <80.00%> (-0.14%)	⬇️
samples-tests-java21	32.05% <80.00%> (-0.07%)	⬇️
samples-tests-java8	29.82% <80.00%> (-0.01%)	⬇️
unit-tests-java11	59.03% <80.00%> (+<0.01%)	⬆️
unit-tests-java17	58.52% <80.00%> (+0.01%)	⬆️
unit-tests-java21	58.50% <80.00%> (+<0.01%)	⬆️
unit-tests-java25	58.48% <80.00%> (+0.01%)	⬆️
unit-tests-java8	59.02% <80.00%> (+0.01%)	⬆️

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[heliang666s]

LTGM

[zrlw]

LGTM