For better integration with the Lucene Test Framework and the
availabilty of RandomizedRunner / Randommized Testing this commit
moves over from TestNG to JUnit.
This commit also moves relevant places over to RandomzedRunner for
reproduceability and removes copied classes from the Lucene Test
Framework.
This enforces that settings are taken into account whichever mean is used to
import the project into Eclipse (manual import, m2e, mvn eclipse:eclipse, ...).