KAFKA-6607: Commit correct offsets for transactional input data

[mjsax]

Port of #8040 to trunk -- the only real difference is the missing check of we are in pending shutdown and a task is not found -- in trunk we always create all new task hence this check is not necessary.

\cc @guozhangwang

[guozhangwang]

LGTM! In trunk we can be stricter and throw illegal-state since we should always have the tasks at hand still.

[mjsax]

Rebased this PR to resolve merge conflicts.

[mjsax]

Java 8 passed.
Java 11: kafka.api.ConsumerBounceTest.testRollingBrokerRestartsWithSmallerMaxGroupSizeConfigDisruptsBigGroup

Retest this please.

[mjsax]

Java 8:

kafka.admin.DeleteConsumerGroupsTest.testDeleteWithMixOfSuccessAndError
kafka.admin.DescribeConsumerGroupTest.testDescribeGroupWithShortInitializationTimeout
kafka.admin.ResetConsumerGroupOffsetTest.testResetOffsetsAllTopicsAllGroups
kafka.admin.DescribeConsumerGroupTest.testDescribeGroupMembersWithShortInitializationTimeout
kafka.admin.DeleteConsumerGroupsTest.testDeleteCmdWithMixOfSuccessAndError

Java 11: kafka.admin.DescribeConsumerGroupTest.testDescribeGroupWithShortInitializationTimeout

Those are different test than in the run before. Merging this.