main.events_restart failed in buildbot on Windows

main.events_restart                      w1 [ fail ]  Found warnings/errors in server log file!

        Test ended at 2017-03-01 11:23:45

line

170301 11:23:40 [ERROR] mysqld got exception 0xc0000005 ;

Attempting backtrace. You can use the following information to find out

2017-03-01 11:23:40 6080 [ERROR] Plugin 'MyISAM' has ref_count=6 after shutdown.

^ Found warnings in D:/win32-debug/build/mysql-test/var/1/log/mysqld.1.err

ok

 - saving 'D:/win32-debug/build/mysql-test/var/1/log/main.events_restart/' to 'D:/win32-debug/build/mysql-test/var/log/main.events_restart/'