[FLINK-14041][tests] Refactor LeaderRetrievalServiceHostnameResolutionTest and remove StandaloneUtils

[tisonkun]

What is the purpose of the change

StandaloneUtils is a poor utility that can be just replace with HighAvailabilityServicesUtils on its only usages.

Propose to refactor LeaderRetrievalServiceHostnameResolutionTest and remove StandaloneUtils.

Brief change log

• Refactor LeaderRetrievalServiceHostnameResolutionTest to use HighAvailabilityServicesUtils
• Remove StandaloneUtils

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable)

cc @zentol

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[zentol]

Not sure if we should rely on the HAservices in this test; we only want to test the LeaderRetrievalService, but hte HAServices pull in several other dependencies.

[tisonkun]

Thanks for your review @zentol ! I can see your concern here.

Actually the original tests test AkkaRpcServicesUtils#getRpcUrl and since that StandaloneUtils is never used outside these tests it seems we tests nothing about abstract leader retrieval service. In fact, the retrieval of WebMonitor is a bit different from AkkaRpcServicesUtils#getRpcUrl(said it is HighAvailabilityServicesUtils#getWebMonitorAddress). I think we can even guard by AkkaUtilsTest and maybe add a dedicate test for HighAvailabilityServicesUtils#getWebMonitorAddress and delete LeaderRetrievalServiceHostnameResolutionTest because it doesn't test something at that abstraction level.

[tisonkun]

What do you think @zentol ?

[tisonkun]

close with another approach.