Revisit `display: contents` accessibility once more thorough API is available

[cookiecrook]

Once we have more API available to test (like isIgnored), we should revisit display: contents and do more thorough testing.

Originally posted by @cookiecrook in https://github.com/web-platform-tests/interop-accessibility/issues/60#issuecomment-1894438186

Update from @rahimabdi in https://github.com/web-platform-tests/wpt/pull/43740#discussion_r1449600711

• [ ] Keyboard focusability of display:contents controls (https://github.com/mozilla/standards-positions/issues/772)
• [ ] Reading order of accessibility elements such as table cells
• [ ] Expected keyboard operability such as controls being focusable, links remaining operable with Enter/Return
• [ ] Ensuring elements are exposed appropriately as a result of display: contents (needs isIgnored or similar)
• [ ] <table> structure such as accessibility row or column count