[REG: 5.7->5.8] Multibyte unicode characters are not working with MySQL

Now Qt enables utf8mb4 for proper utf8 support in MySQL if it supports it. Unfortunately rest of the plugin code still assumes MySQL does not support utf-8 and translates every query with system codec. When trying to run:

    query.exec("INSERT INTO table (description) VALUES ('æøå')");

It throws out:

"Incorrect string value: '\\xE6\\xF8\\xE5' for column 'description' at row 1 QMYSQL: Unable to execute query"

These characters appear to be in latin1 encoding.