innodb.innodb-index-online-fk fails with mismatch on Windows, prints garbage instead of column name

innodb.innodb-index-online-fk 'innodb_plugin' w1 [ fail ]

        Test ended at 2017-08-30 09:41:12

CURRENT_TEST: innodb.innodb-index-online-fk

--- D:/winx64-debug/build/src/mysql-test/suite/innodb/r/innodb-index-online-fk.result	2017-08-30 09:14:12.289859900 +0000

+++ D:\winx64-debug\build\src\mysql-test\suite\innodb\r\innodb-index-online-fk.reject	2017-08-30 09:41:12.431537400 +0000

@@ -279,7 +279,7 @@

 ADD CONSTRAINT fk_1 FOREIGN KEY (a2) REFERENCES parent(b)

 ON DELETE SET NULL ON UPDATE CASCADE,

 ALGORITHM = INPLACE;

-ERROR 42000: Key column 'a2' doesn't exist in table

+ERROR 42000: Key column ' ' doesn't exist in table

 ALTER TABLE child CHANGE a2 a3 INT,

 ADD CONSTRAINT fk_1 FOREIGN KEY (a3) REFERENCES parent(b)

 ON DELETE SET NULL ON UPDATE CASCADE,

mysqltest: Result content mismatch