Test scenario:

1. Create a course
2. Create a quiz inside that course
3. Create a question of type "Embedded answers (cloze)"
4. As question content, enter the example provided in Moodle official documentation (https://docs.moodle.org/31/en/Embedded_Answers_(Cloze)_question_type)
5. Under /admin/filters.php, make sure "HTML tidy" filter is "Off"
6. Start an attempt of the quiz
7. The embedded answers textfields are rendered properly (see screenshot)
8. Under /admin/filters.php, turn on "HTML tidy" filter
9. Verify PHP is built with "tidy" extension 
10. Resume the quiz attempt
11. Some embedded answers textfields are not rendered (i.e. the qtypemultianswerNmarker are not replaced).