[SCB-1450] Microservice instance may get stuck when watch connection to sc is recovered and pulling instance action is executed in eventloop thread

[HuaiJoe]

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[coveralls]

Coverage increased (+0.1%) to 85.896% when pulling 296b005 on HuaiJoe:master into 350e988 on apache:master.

[liubao68]

Can you please check if config-cc has the same problem?

[HuaiJoe]

Can you please check if config-cc has the same problem?

Config Center client may come across the same problem as Service Center client.I will create a issue and fix it later.