This includes:
- changing all usernames in feature to lowercase, for cross-db passing. Fixes:
- user/tests/behat/set_email_display.feature
- ensure that course_enrolment_manager::get_potential_users() and
external always returns user->maildisplay attribute, so email
visibility can be calculated by user_get_user_details(). Fixes:
- enrol/tests/behat/enrol_user.feature
- blocks/news_items/tests/behat/display_news.feature
- course/tests/behat/course_creation.feature