main.mysql_upgrade failed in buildbot: FATAL ERROR: Upgrade failed

main.mysql_upgrade 'innodb'              w2 [ fail ]

        Test ended at 2019-07-19 16:19:05

CURRENT_TEST: main.mysql_upgrade

mysqltest: At line 74: exec of 'D:\win32-packages\build\client\RelWithDebInfo\mysql_upgrade.exe --defaults-file=D:/win32-packages/build/mysql-test/var/2/my.cnf --force 2>&1' failed, error: 1, status: 1, errno: 0

Output from before failure:

Version check failed. Got the following error when calling the 'mysql' command line client

""D:\win32-packages\build\client\RelWithDebInfo\mysqlcheck.exe" {hF�FATAL ERROR: Upgrade failed

The result from queries just before the failure was:

< snip >

Phase 4/7: Running 'mysql_fix_privilege_tables'

Phase 5/7: Fixing table and database names

Phase 6/7: Checking and upgrading tables

Processing databases

information_schema

mtr

mtr.global_suppressions                            OK

mtr.test_suppressions                              OK

performance_schema

test

Phase 7/7: Running 'FLUSH PRIVILEGES'

OK

DROP USER mysqltest1@'%';

Version check failed. Got the following error when calling the 'mysql' command line client

ERROR 1045 (28000): Access denied for user 'mysqltest1'@'localhost' (using password: YES)

FATAL ERROR: Upgrade failed

Run mysql_upgrade with a non existing server socket

mysqlcheck: Got error: 2005: Unknown MySQL server host 'not_existing_host' (errno) when trying to connect

FATAL ERROR: Upgrade failed

set GLOBAL sql_mode='STRICT_ALL_TABLES,ANSI_QUOTES,NO_ZERO_DATE';

More results from queries before failure can be found in D:\win32-packages\build\mysql-test\var\2\log\mysql_upgrade.log