Test show_processlist is unstable

http://jenkins.percona.com/job/percona-server-5.5-trunk/619/BUILD_TYPE=debug,Host=centos5-64/consoleText:

main.show_processlist w3 [ fail ]
        Test ended at 2016-08-10 06:32:06

CURRENT_TEST: main.show_processlist
--- /mnt/workspace/percona-server-5.5-trunk/BUILD_TYPE/debug/Host/centos5-64/mysql-test/r/show_processlist.result 2016-07-27 21:03:35.585092347 +0300
+++ /mnt/workspace/percona-server-5.5-trunk/BUILD_TYPE/debug/Host/centos5-64/mysql-test/r/show_processlist.reject 2016-08-10 13:32:05.719680907 +0300
@@ -12,6 +12,7 @@
 SET DEBUG_SYNC='now SIGNAL go';
 connection default;
 Id User Host db Command Time State Info Rows_sent Rows_examined Rows_read
+<Id> root <Host> NULL <Command> <Time> <State> <Info> X X X
 <Id> root <Host> test <Command> <Time> <State> <Info> X X X
 <Id> root <Host> test <Command> <Time> <State> <Info> X X X
 <Id> root <Host> test <Command> <Time> <State> <Info> X X X

mysqltest: Result content mismatch