MINOR: remove useless repeated method call in KafkaApiTest

[dengziming]

More detailed description of your change
SetReplicas was invoked twice with same params, I think the author means setIsrs

Summary of testing strategy (including rationale)
QA

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[dengziming]

@ijuma Hello, this is your code, PTAL.

[chia7712]

@dengziming nice find and thanks for your patch.

There are 94 test cases but no one does use ISR info?

[ijuma]

LGTM. It may make sense to assert this in some test too.

[dengziming]

@chia7712 , I checked the code again and found no one uses ISR info. In fact this code is copied when replacing req/resp with auto-generated protocol in #7353, and the original code set ISR=allReplicas.

[chia7712]

the original code set ISR=allReplicas.

Could you share the link to me? thanks!

[dengziming]

@chia7712 , see https://github.com/apache/kafka/pull/7353/files#diff-d418e862d65bd68453ec359a3b4f08e38be8948b4d772909ece6ff2a07e5f714L818