perf-simple-query: add cpu_cycles / op metric
Example output:
```
bhalevy@[] scylla$ build/release/scylla perf-simple-query --default-log-level=error -c 1 --duration 10
random-seed=4058714023
enable-cache=1
Running test with config: {partitions=10000, concurrency=100, mode=read, frontend=cql, query_single_key=no, counters=no}
Disabling auto compaction
Creating 10000 partitions...
86912.75 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42346 insns/op, 22811 cycles/op, 0 errors)
91348.29 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42306 insns/op, 22362 cycles/op, 0 errors)
87965.84 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42338 insns/op, 22966 cycles/op, 0 errors)
90793.67 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42351 insns/op, 22783 cycles/op, 0 errors)
90104.27 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42358 insns/op, 22875 cycles/op, 0 errors)
90397.13 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42355 insns/op, 22735 cycles/op, 0 errors)
89142.39 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.2 tasks/op, 42363 insns/op, 22996 cycles/op, 0 errors)
90410.40 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 42363 insns/op, 22725 cycles/op, 0 errors)
88173.10 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.2 tasks/op, 42366 insns/op, 23160 cycles/op, 0 errors)
88416.51 tps ( 63.1 allocs/op, 0.0 logallocs/op, 14.2 tasks/op, 42379 insns/op, 23102 cycles/op, 0 errors)
median 90104.26849997675
median absolute deviation: 1244.02
maximum: 91348.29
minimum: 86912.75
```
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closes scylladb/scylladb#18818
fb3db7d81f