Enable logging for all modules' test suites

Some modules do not log anything, not even to the console, because they don't have a log4j.xml file in their classpath (e.g. cdi). Because of this, errors in jenkins are harder to spot and to fix.

We should ensure that each module has a log4j configuration file in the test classpath (or maybe use a system property to configure a generic log4j.xml in the root directory). Preferably each module should have its own log file, but they could use the same log file as long as they don't truncate it.