main.mysqld_option_err failed in buildbot with wrong error

main.mysqld_option_err                   w2 [ fail ]

        Test ended at 2019-11-08 16:42:45

CURRENT_TEST: main.mysqld_option_err

mysqltest: At line 47: command "$MYSQLD_BOOTSTRAP_CMD --skip-networking --datadir=$MYSQLTEST_VARDIR/tmp/mysqld_option_err --skip-grant-tables --plugin-dir=$MYSQLTEST_VARDIR/plugins --plugin-load=example=ha_example.so --plugin-example-enum-var=noexist >>$MYSQLTEST_VARDIR/tmp/mysqld_option_err/mysqltest.log 2>&1" failed with wrong error: 3

The result from queries just before the failure was:

Test that unknown option is not silently ignored.

Test bad binlog format.

Test bad default storage engine.

Test non-numeric value passed to number option.

Test that bad value for plugin enum option is rejected correctly.

 - saving 'D:/winx64-debug/build/mysql-test/var/2/log/main.mysqld_option_err/' to 'D:/winx64-debug/build/mysql-test/var/log/main.mysqld_option_err/'