Follow-up SVG tests

[cookiecrook]

Tracker for the items from #69 that were blocked or punted from the Interop 2023 Accessibility Investigation.

• Add SVG-specific "name from content" tests #79
• Add SVG default-role-for-element tests #81
• Add SVG Tree Inclusion tests #82
• Add SVG name fallback tests from aria attrs to host lang title etc #84

Once all the above subtasks are complete:

• Go back and verify none of the research, tasks, and cross-references for Write tests for SVG-AAM role mapping #69 were overlooked

[cookiecrook]

#84 looks like it's unblocked, but the rest are waiting on SVG-AAM response from the SVG working group. Unless that repo were taken over by ARIA WG, 4 out of the 5 subtasks are out-of-scope for the 2024 investigation.