MINOR: Code cleanup in StreamsResetter

[mjsax]

More detailed description of your change,
if necessary. The PR title and PR message become
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Summary of testing strategy (including rationale)
for the feature or bug fix. Unit and/or integration
tests are expected for any behaviour change and
system tests should be considered for larger changes.

Committer Checklist (excluded from commit message)

• Verify design and implementation
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• Verify documentation (including upgrade notes)

[mjsax]

Call for review @guozhangwang @bbejeck @vvcephei

[bbejeck]

Thanks @mjsax LGTM

[bbejeck]

retest this please

[vvcephei]

LGTM. Thanks for the separate code-cleanup PR.

[mjsax]

Java11: https://builds.apache.org/job/kafka-pr-jdk11-scala2.12/535/

Test Result (14 failures / -1)

kafka.admin.ResetConsumerGroupOffsetTest.testResetOffsetsNotExistingGroup
kafka.api.CustomQuotaCallbackTest.testCustomQuotaCallback
kafka.api.PlaintextConsumerTest.testLowMaxFetchSizeForRequestAndPartition
kafka.api.SaslMultiMechanismConsumerTest.testCoordinatorFailover
kafka.api.SaslPlainPlaintextConsumerTest.testCoordinatorFailover
kafka.api.SaslSslAdminClientIntegrationTest.testAclDescribe
kafka.api.SaslSslAdminClientIntegrationTest.testLegacyAclOpsNeverAffectOrReturnPrefixed
kafka.api.SaslSslConsumerTest.testCoordinatorFailover
kafka.api.SslConsumerTest.testCoordinatorFailover
kafka.tools.MirrorMakerIntegrationTest.testCommaSeparatedRegex
org.apache.kafka.streams.integration.RepartitionWithMergeOptimizingIntegrationTest.shouldSendCorrectRecords_OPTIMIZED
org.apache.kafka.streams.integration.ResetIntegrationTest.shouldNotAllowToResetWhenInputTopicAbsent
org.apache.kafka.streams.integration.ResetIntegrationWithSslTest.testReprocessingFromScratchAfterResetWithIntermediateUserTopic
org.apache.kafka.streams.integration.SuppressionIntegrationTest.shouldSuppressIntermediateEventsWithRecordLimit

Java8:

kafka.api.PlaintextConsumerTest.testCoordinatorFailover
kafka.api.SslConsumerTest.testCoordinatorFailover

Retest this please