[Java] Made perf tests run with latest JMH version 

JMH test tool went GA, so I updated the jars inside the project and also a minor change was done for the benchmark code.
I updated at the same time the build file that runs the tests. It is not needed to bundle all classes and libs in a big jar file so I changed it in the way that the microbenchmark jar file only contains the test code and generated classes.

Beside this I fixed a compilation problem. 

Thanks