The average time compute for clickbench query is wrong

[zhuqi-lucas]

Describe the bug

The average time compute for clickbench query is wrong when we run all the queries besides single query.

It was added in:

#15381

To Reproduce

Q42: SELECT DATE_TRUNC('minute', to_timestamp_seconds("EventTime")) AS M, COUNT(*) AS PageViews FROM hits WHERE "CounterID" = 62 AND "EventDate"::INT::DATE >= '2013-07-14' AND "EventDate"::INT::DATE <= '2013-07-15' AND "IsRefresh" = 0 AND "DontCountHits" = 0 GROUP BY DATE_TRUNC('minute', to_timestamp_seconds("EventTime")) ORDER BY DATE_TRUNC('minute', M) LIMIT 10 OFFSET 1000;
Query 42 iteration 0 took 52.7 ms and returned 10 rows
Query 42 iteration 1 took 48.1 ms and returned 10 rows
Query 42 iteration 2 took 53.8 ms and returned 10 rows
Query 42 iteration 3 took 52.8 ms and returned 10 rows
Query 42 iteration 4 took 50.2 ms and returned 10 rows
Query 42 avg time: 1121.93 ms

Expected behavior

It should be right.

Additional context

[zhuqi-lucas]

take