Tests: Migrate JUnit 3 tests to JUnit 4.
tests: Migrate flease and foundation tests to JUnit 4.
tests: Standardize test initialization method names.
Merge remote-tracking branch 'main/master' into jdillmann-junit3to4

Conflicts:
	java/servers/test/org/xtreemfs/test/osd/OSDTruncateTest.java
Merge pull request #334 from xtreemfs/jdillmann-junit3to4

Migrate JUnit 3 tests to JUnit 4