fieldset should force used value of 'display' for some values

Part of https://github.com/whatwg/html/issues/3660

Fieldset needs to override used 'display' for some values.

inline, inline-block, inline-table, ruby, ruby-* -> inline-block
block, table, table-*, list-item, run-in, flow, flow-root -> block

These should work: none, flex, inline-flex, grid, inline-grid, contents, layout() ?