Updated log message

so that it does not look that initialization of classloader cache takes so long. (Down the road it will not be a 'lifecycle' level message anyway).
Added basic performance test for classloaders caching

- Needed to give generous max time regression because current master is slower that previous versions.
- Tweaked the machinery so that it is possible to test with long running process. It can be still improved.
- Started forking the test runs. It's simpler this way.