Although in visual order the quiz contents come first, in source order the question bank comes first and editing quizzes is difficult for screen reader users, for instance. With proper CSS, the real solution would be to change the source order so that the primary content, the quiz questions, come first. This can get tricky though.

One quick fix is to add a skip link to quiz content, however, as skip links are not used in Moodle elsewhere, either, the implementation details of skip links should be resolved Moodle-wide first: MDL-7738

http://www.webaim.org/techniques/skipnav/