Fixed missing operation counts in performance tests

Fixed missing operation counts in performance tests, which were dropped because their count was under the performanceUpdateFrequency. They are now logged at least at the end of the test. The magic line of code is:
```java
operations.addAndGet(iteration % performanceUpdateFrequency);
```

Updated ExampleTests with OperationSelector and fixed performance measurement.

Removed some warnings in test classes.
it doesn't matter - they don't log the last batch anyway, do they? you fixed it here, but then you should switch the order as I said.