[hotfix][yarn-tests] Replaces runtime by timestamp

The intend is to improve local debugging matching log events in different log
files (YARN, Flink) via the timestamp.

Author: XComp

flink-yarn-tests/src/test/resources/log4j2-test.properties

@@ -25,7 +25,7 @@ appender.testlogger.name = TestLogger
 appender.testlogger.type = CONSOLE
 appender.testlogger.target = SYSTEM_ERR
 appender.testlogger.layout.type = PatternLayout
-appender.testlogger.layout.pattern = %-4r [%t] %-5p %c %x - %m%n
+appender.testlogger.layout.pattern = %d [%t] %-5p %c %x - %m%n
 
 logger.hadoop.name = org.apache.hadoop
 logger.hadoop.level = OFF