[testclient] Multiple calls to printAggregatedStats result in inaccur…

[tomscut]

Fixes #ISSUE-13250

Motivation

We repeatedly call #printAggregatedStats in those places, which ultimately calls Record#getIntervalHistogram. The startTimestamp and endTimestamp will be reset, which may result in inconsistent results of multiple access.

We should only call printAggregatedStats once inside ShutdownHook, like PerformanceClient.

Runtime.getRuntime().addShutdownHook(new Thread(() -> {
    printAggregatedThroughput(start);
    printAggregatedStats();
}));

Modifications

Remove redundant calls to #printAggregatedStats.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: (no)
• The schema: (no)
• The default values of configurations: (no)
• The wire protocol: (no)
• The rest endpoints: (no)
• The admin cli options: (no)
• Anything that affects deployment: (no)

Documentation

• doc-required
• no-need-doc
• doc

[tomscut]

Thanks @merlimat and @yuruguo for your review.