Fallback table for required attribute values needs updating

[carmacleod]

There are inconsistencies between the spec and the fallback table for missing required attributes.

Here are the items that need fixing in order to bring the fallback table in line with the spec:

• Fallback table rows should be sorted alphabetically by role to be consistent with spec
• Remove combobox aria-haspopup from fallback table (spec says it's supported, not required)
• Add combobox aria-controls to fallback table with fallback value of "no mapping"
• Remove menuitem aria-haspopup from fallback table (spec says it's supported, not required)
• Remove scrollbar aria-orientation from fallback table (spec says it's supported, not required)
• Remove spinbutton aria-valuemax, aria-valuemin and aria-valuenow from fallback table (spec says they're supported, not required)

These are covered in other issues/PRs:

• Add meter aria-valuenow to fallback table (covered in PR revise meter authoring advice #1129)
• Add meter aria-valuemax and aria-valuemin to fallback table (PR revise meter authoring advice #1129 makes them "supported")
• Add option aria-selected to fallback table (depends on issue Option role: Change aria-selected from required to supported and remove default value #799)