main.bootstrap fails sporadically in buildbot on Windows

main.bootstrap                           w4 [ fail ]

        Test ended at 2016-06-26 18:38:17

CURRENT_TEST: main.bootstrap

mysqltest: At line 45: command "$MYSQLD_BOOTSTRAP_CMD < $MYSQLTEST_VARDIR/tmp/long_query.sql >> $MYSQLTEST_VARDIR/tmp/bootstrap.log 2>&1" failed with wrong error: 255

The result from queries just before the failure was:

drop table if exists t1;

drop table t1;

drop table t1;

ERROR 42S02: Unknown table 'test.t1'

set @my_max_allowed_packet= @@max_allowed_packet;

set global max_allowed_packet=100*@@max_allowed_packet;

 - saving 'D:/winx64-packages/build/mysql-test/var/4/log/main.bootstrap/' to 'D:/winx64-packages/build/mysql-test/var/log/main.bootstrap/'

 - found 'mysqld.dmp' (0/5)

Retrying test main.bootstrap, attempt(2/3)...

worker[4] > Restart  - not started