[hotfix] [tests] Tests in flink-tests suppress log output by default

flink-tests/src/test/resources/log4j-test.properties

@@ -18,7 +18,7 @@
 
 # Set root logger level to OFF to not flood build logs
 # set manually to INFO for debugging purposes
-log4j.rootLogger=INFO, testlogger
+log4j.rootLogger=OFF, testlogger
 
 # A1 is set to be a ConsoleAppender.
 log4j.appender.testlogger=org.apache.log4j.ConsoleAppender
@@ -28,4 +28,4 @@ log4j.appender.testlogger.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
 
 # suppress the irrelevant (wrong) warnings from the netty channel handler
 log4j.logger.org.jboss.netty.channel.DefaultChannelPipeline=ERROR
-log4j.logger.org.apache.zookeeper=OFF
\ No newline at end of file
+log4j.logger.org.apache.zookeeper=OFF