Write all unit test output to a file

bagel/src/test/resources/log4j.properties

 # Set everything to be logged to the console
-log4j.rootCategory=WARN, console
-log4j.appender.console=org.apache.log4j.ConsoleAppender
-log4j.appender.console.layout=org.apache.log4j.PatternLayout
-log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %p %c{1}: %m%n
+log4j.rootCategory=INFO, file
+log4j.appender.file=org.apache.log4j.FileAppender
+log4j.appender.file.append=false
+log4j.appender.file.file=spark-tests.log
+log4j.appender.file.layout=org.apache.log4j.PatternLayout
+log4j.appender.file.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %p %c{1}: %m%n
 
 # Ignore messages below warning level from Jetty, because it's a bit verbose
 log4j.logger.org.eclipse.jetty=WARN

core/src/test/resources/log4j.properties

 # Set everything to be logged to the console
-log4j.rootCategory=WARN, console
-log4j.appender.console=org.apache.log4j.ConsoleAppender
-log4j.appender.console.layout=org.apache.log4j.PatternLayout
-log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %p %c{1}: %m%n
+log4j.rootCategory=INFO, file
+log4j.appender.file=org.apache.log4j.FileAppender
+log4j.appender.file.append=false
+log4j.appender.file.file=spark-tests.log
+log4j.appender.file.layout=org.apache.log4j.PatternLayout
+log4j.appender.file.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %p %c{1}: %m%n
 
 # Ignore messages below warning level from Jetty, because it's a bit verbose
 log4j.logger.org.eclipse.jetty=WARN

repl/src/test/resources/log4j.properties

 # Set everything to be logged to the console
-log4j.rootCategory=WARN, console
-log4j.appender.console=org.apache.log4j.ConsoleAppender
-log4j.appender.console.layout=org.apache.log4j.PatternLayout
-log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %p %c{1}: %m%n
+log4j.rootCategory=INFO, file
+log4j.appender.file=org.apache.log4j.FileAppender
+log4j.appender.file.append=false
+log4j.appender.file.file=spark-tests.log
+log4j.appender.file.layout=org.apache.log4j.PatternLayout
+log4j.appender.file.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %p %c{1}: %m%n
 
 # Ignore messages below warning level from Jetty, because it's a bit verbose
 log4j.logger.org.eclipse.jetty=WARN