Fix cluster benchmark README.md #3741

Job	Run time
lint	11m 53s
examples (stable, memstore)	51s
openraft-feature-test (nightly)	54s
examples (stable, raft-kv-memstore)	2m 26s
openraft-test (stable, 0)	3m 32s
openraft-feature-test (nightly, serde)	51s
examples (stable, raft-kv-memstore-network-v2)	1m 2s
cluster-benchmark (cluster_benchmark)	47s
openraft-test (nightly, 30)	3m 38s
openraft-feature-test (nightly, single-term-leader)	53s
examples (stable, raft-kv-memstore-opendal-snapshot-data)	1m 25s
openraft-test (nightly, 0, single-term-leader)	3m 17s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	52s
examples (stable, raft-kv-memstore-singlethreaded)	1m 7s
openraft-test-bench (nightly)	58s
examples (stable, raft-kv-rocksdb)	8m 14s
Build (nightly, bench,serde,bt,singlethreaded)	51s
stores (stores/memstore)	52s
examples (nightly, memstore)	57s
stores (stores/rocksstore)	6m 19s
examples (nightly, raft-kv-memstore)	2m 25s
tests-feature-test (nightly)	2m 57s
stores (stores/sledstore)	1m 9s
examples (nightly, raft-kv-memstore-network-v2)	1m 20s
tests-feature-test (nightly, single-term-leader)	2m 59s
examples (nightly, raft-kv-memstore-opendal-snapshot-data)	1m 54s
tests-feature-test (nightly, loosen-follower-log-revert)	3m 4s
examples (nightly, raft-kv-memstore-singlethreaded)	1m 24s
examples (nightly, raft-kv-rocksdb)	12m 57s
	1h 21m 48s

Provide feedback