Merge a test case and a code change from MySQL 5.7.22.
There was no commit message, but a test case was included.
https://github.com/mysql/mysql-server/commit/d3ec326bcd8352fcd969dbfd54e5c604db9cd30b

There is no Bug 25899959 mentioned in the MySQL 8.0.11 history.
Based on the number, it should have been filed before August 2017.
Maybe it was initially fixed in a not-yet-public MySQL 9.0 branch?

The code change differs from MySQL 5.7, because the mbminmaxlen
were split in MariaDB in MDEV-7049.