Make integration tests faster (eg. finished in less than 3 minutes)

[suzaku]

The task of running integration tests is the bottleneck of the build pipeline.
We may try to make it faster by:

1. Reducing the number of SQLs tested, may be some of the tests should belong to chaos testing instead of integration testing;
2. Split the task into multiple ones and run them in parallel

[july2993]

3 minute..?
i think we can first make the test case in tests/dailytest run in parallel.

[suzaku]

@july2993 Yes, @jebter mentioned that some other projects in our team are limiting the run time of integration tests to 3 minute by running them in parallel.