[Dubbo-2.7.2] fix registery urls increase forever when recreate reference proxy

[vio-lin]

fix issue #4107

What is the purpose of the change

when client retry init reference, clear registry urls to avoid OOM.
the registry url contains timestamp value, it can not change urls from list to set.

Brief changelog

do clear urls when in create remote proxy

Verifying this change

do clear urls when create remote proxy

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[codecov-io]

Codecov Report

Merging #4109 into master will increase coverage by 0.04%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master    #4109      +/-   ##
============================================
+ Coverage     62.63%   62.68%   +0.04%     
- Complexity      543      545       +2     
============================================
  Files           762      762              
  Lines         32752    32753       +1     
  Branches       5162     5162              
============================================
+ Hits          20515    20530      +15     
+ Misses         9876     9862      -14     
  Partials       2361     2361

Impacted Files	Coverage Δ	Complexity Δ
.../java/org/apache/dubbo/config/ReferenceConfig.java	59.85% <100%> (+0.14%)	0 <0> (ø)	⬇️
...ache/dubbo/remoting/transport/AbstractChannel.java	75% <0%> (-12.5%)	0% <0%> (ø)
.../apache/dubbo/remoting/transport/AbstractPeer.java	63.04% <0%> (ø)	0% <0%> (ø)	⬇️
...dubbo/remoting/exchange/support/DefaultFuture.java	75.16% <0%> (+1.96%)	0% <0%> (ø)	⬇️
...e/dubbo/remoting/transport/netty/NettyChannel.java	62.35% <0%> (+4.7%)	21% <0%> (+1%)	⬆️
...che/dubbo/remoting/transport/mina/MinaChannel.java	53.94% <0%> (+10.52%)	17% <0%> (+1%)	⬆️

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[Moriadry-zz]

Hi, this line will change the logic of urls, we will lose contents of urls every time calling createProxy method . I believe it's not a good way to prevent infinite retries and OOM.

How do u think?

[vio-lin]

this urls

Hi, this line will change the logic of urls, we will lose contents of urls every time calling createProxy method . I believe it's not a good way to prevent infinite retries and OOM.
How do u think?

I think this createProxy() is a method to get a new client. It happended when last getProxy() failed and
initialized = false. It isn't nessary to keep the old,failed urls of reference , when we getProxy next time.
As the description of urls The url of the reference service，we should keep the last and success urls.

[beiwei30]

LGTM.