Some strings in backup Moodle1 unit tests need updating

Some of the Moodle1 unit tests contain test strings that could raise security/content concerns for hosting providers, or developers viewing the code. They should be updated to reference more professional test strings.

Relevant file: /backup/converter/moodle1/tests/moodle1_converter_test.php

The following methods should be updated:

• test_referenced_course_files()
• test_referenced_files_urlencoded()