Implemented code review comments,

improved the result file readability.

mysql-test/suite/perfschema/r/relaylog.result

@@ -17,6 +17,7 @@ FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_
 select * from performance_schema.file_summary_by_instance
 where file_name like "%slave-%" order by file_name;
 FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_OF_BYTES_WRITE
+"Expect a master binlog + binlog_index"
 select * from performance_schema.file_summary_by_instance
 where event_name like "%binlog%" order by file_name;
 FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_OF_BYTES_WRITE
@@ -35,6 +36,7 @@ wait/synch/cond/sql/MYSQL_BIN_LOG::COND_prep_xids	0
 wait/synch/cond/sql/MYSQL_BIN_LOG::update_cond	1
 wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index	3
 wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_prep_xids	0
+"Expect no slave relay log"
 select * from performance_schema.file_summary_by_instance
 where event_name like "%relaylog%" order by file_name;
 FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_OF_BYTES_WRITE
@@ -60,6 +62,7 @@ FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_
 [DATADIR]slave-relay-bin.000001	wait/io/file/sql/relaylog	4	3	370	263
 [DATADIR]slave-relay-bin.000002	wait/io/file/sql/relaylog	2	4	368	368
 [DATADIR]slave-relay-bin.index	wait/io/file/sql/relaylog_index	2	4	50	125
+"Expect a slave binlog + binlog_index"
 select * from performance_schema.file_summary_by_instance
 where event_name like "%binlog%" order by file_name;
 FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_OF_BYTES_WRITE
@@ -78,6 +81,7 @@ wait/synch/cond/sql/MYSQL_BIN_LOG::COND_prep_xids	0
 wait/synch/cond/sql/MYSQL_BIN_LOG::update_cond	0
 wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index	5
 wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_prep_xids	0
+"Expect a slave relay log"
 select * from performance_schema.file_summary_by_instance
 where event_name like "%relaylog%" order by file_name;
 FILE_NAME	EVENT_NAME	COUNT_READ	COUNT_WRITE	SUM_NUMBER_OF_BYTES_READ	SUM_NUMBER_OF_BYTES_WRITE

mysql-test/suite/perfschema/t/relaylog.test

@@ -44,7 +44,7 @@ select * from performance_schema.file_summary_by_instance
 select * from performance_schema.file_summary_by_instance
   where file_name like "%slave-%" order by file_name;
 
-# Expect a master binlog + binlog_index
+-- echo "Expect a master binlog + binlog_index"
 
 --replace_result $MYSQLD_DATADIR [DATADIR]
 select * from performance_schema.file_summary_by_instance
@@ -57,7 +57,7 @@ select event_name, count_star
   from performance_schema.events_waits_summary_global_by_event_name
   where event_name like "%MYSQL_BIN_LOG%" order by event_name;
 
-# Expect no slave relay log.
+-- echo "Expect no slave relay log"
 
 --replace_result $MYSQLD_DATADIR [DATADIR]
 select * from performance_schema.file_summary_by_instance
@@ -82,7 +82,7 @@ select * from performance_schema.file_summary_by_instance
 select * from performance_schema.file_summary_by_instance
   where file_name like "%slave-%" order by file_name;
 
-# Expect a slave binlog + binlog_index
+-- echo "Expect a slave binlog + binlog_index"
 
 --replace_result $MYSQLD_DATADIR [DATADIR]
 select * from performance_schema.file_summary_by_instance
@@ -95,7 +95,7 @@ select event_name, count_star
   from performance_schema.events_waits_summary_global_by_event_name
   where event_name like "%MYSQL_BIN_LOG%" order by event_name;
 
-# Expect a slave relay log.
+-- echo "Expect a slave relay log"
 
 --replace_result $MYSQLD_DATADIR [DATADIR]
 select * from performance_schema.file_summary_by_instance