KAFKA-20338: More KRaft JMH benchmarks

[anjy7]

The work in this PR is a followup to #22669

This PR covers:

• FollowerBenchmarks (the follower path): handling a BEGIN_QUORUM_EPOCH one epoch ahead, handling an END_QUORUM_EPOCH from the leader, and appending records from a FETCH response, both the case that commits nothing (high watermark unchanged) and the case that advances the follower's high watermark and notifies its listener (a log read-back).

• ElectionBenchmarks (the election-start path): 4 new state-transition benchmarks :

1. Unattached → Prospective → Unattached (returning to Unattached via a higher-epoch vote request)
2. Unattached → Prospective → Unattached (returning via the prospective's own election timeout)
3. Prospective → Candidate → Prospective
4. Follower → Prospective → Follower