Outside of inert container  Inert button

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PASS Button outside of inert container is focusable.
PASS Button with inert atribute is unfocusable.
PASS All focusable elements inside inert subtree are unfocusable
PASS Can get inert via property
PASS Elements inside of inert subtrees return false when getting 'inert'
PASS Setting inert via property correctly modifies inert state