- Do not mix latin1 and utf8 in the test and result file.
Not only it looks strange, and it does not work on Windows either.
- Fix --default-character-set usage in mariadb-import.
Prior to patch it was just using platform default when communicating
with server. Now, it uses the charset provided by the option.
- Use --default-character-set=utf8mb4 in test, to have
uniform output across different OSes.