Change logger.log to System.out to print out one line for each file that is handled...

Change logger.log to System.out to print out one line for each file that is handled in the test, otherwise it is sometimes impossible to see where the test stopped (e.g. on timeout), enabling POILogger leads to 400MB logs, which is usually too much to handle...

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1746275 13f79535-47bb-0310-9956-ffa450edef68