MINOR: Remove activeTaskCheckpointableOffsets from AbstractTask

[cadonna]

Committer Checklist (excluded from commit message)

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

[cadonna]

Call for review: @cpettitt-confluent @mjsax @guozhangwang @bbejeck @vvcephei @ableegoldman @abbccdda

[cpettitt-confluent]

Verified this is only used in StreamTask. All for moving Stream/Standby specific stuff out of AbstractTask! LGTM.

[ableegoldman]

Good catch, thanks!

[guozhangwang]

Could you rebase?

[cadonna]

JDK 11/Scala 2.12 failed with

org.scalatest.exceptions.TestFailedException: Consumed 0 records before timeout instead of the expected 1 records

Retest this, please

[cadonna]

JDK 11/Scala 2.12 had the following failing test:

org.apache.kafka.streams.integration.StreamStreamJoinIntegrationTest.testOuterRepartitioned[caching enabled = true]

java.lang.AssertionError: Condition not met within timeout 60000. Did not receive all 1 records from topic outputTopic

Retest this, please

[cadonna]

JDK 11/Scala 2.12 failed because the following test failed:

kafka.admin.DescribeConsumerGroupTest.testDescribeStateWithMultiPartitionTopicAndMultipleConsumers

JDK 11/Scala 2.13 failed because the following test failed:

org.apache.kafka.common.network.SslTransportLayerTest.testListenerConfigOverride

Retest this, please

[cadonna]

In JDK 11/Scala 2.12 the following test failed:

org.apache.kafka.connect.integration.ExampleConnectIntegrationTest.testSourceConnector

JDK 8/Scala 2.11 run into timeout after 4 hours.

Retest this, please

[cadonna]

Retest this, please

[guozhangwang]

LGTM!