[Dubbo-5304]fix unstable ut AbstractMetadataReportFactoryTest

[jasonjoo2010]

It's unstable under multiple network adapters.

What is the purpose of the change

Make it stable.

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[jasonjoo2010]

And ...... who can tell me what happened to the travis? It failed again and again with different but irrelevant errors.

[jasonjoo2010]

related to #5304

[jasonjoo2010]

hi, @chickenlj
Could you spend some time on #4222 ? I have a pr almost finished related on it but need your information.

Thanks