unit test for UrlUtils

[beiwei30]

What is the purpose of the change

#1682: Enhance the test coverage part-4 : dubbo-common/src/main/java/com/alibaba/dubbo/common/status(store|threadpoolutils) modules

Brief changelog

dubbo-common/src/test/java/com/alibaba/dubbo/common/utils/UrlUtilsTest.java

Verifying this change

XXXXX

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[codecov-io]

Codecov Report

Merging #1906 into master will increase coverage by 0.14%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1906      +/-   ##
============================================
+ Coverage      49.4%   49.54%   +0.14%     
- Complexity     4491     4505      +14     
============================================
  Files           558      558              
  Lines         24346    24346              
  Branches       4315     4315              
============================================
+ Hits          12027    12062      +35     
+ Misses        10474    10424      -50     
- Partials       1845     1860      +15

Impacted Files	Coverage Δ	Complexity Δ
...om/alibaba/dubbo/rpc/filter/ActiveLimitFilter.java	77.77% <0%> (-11.12%)	5% <0%> (-2%)
...on/src/main/java/com/alibaba/dubbo/common/URL.java	26.64% <0%> (+0.29%)	80% <0%> (+2%)	⬆️
...rpc/protocol/dubbo/telnet/InvokeTelnetHandler.java	55.69% <0%> (+3.79%)	13% <0%> (+3%)	⬆️
.../java/com/alibaba/dubbo/common/utils/UrlUtils.java	75.98% <0%> (+8.6%)	74% <0%> (+10%)	⬆️
...onfig/spring/extension/SpringExtensionFactory.java	84.61% <0%> (+11.53%)	8% <0%> (ø)	⬇️
...va/com/alibaba/dubbo/config/DubboShutdownHook.java	73.91% <0%> (+30.43%)	6% <0%> (+1%)	⬆️

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