When `ordered_attributes` is set, report attributes to the
StartElementHandler as a flat `[name, value, ...]` list matching
CPython's my_StartElementHandler, instead of always passing a dict.
`xml.etree.ElementTree` and `xml.dom.minidom` (via expatbuilder) both
enable this flag and rely on the flat-list contract, so parsing any
element with attributes previously failed: the dict made `_start` do
integer indexing, raising KeyError which was silently swallowed by the
handler invoker, leaving the tree empty ("missing toplevel element").
Reference (CPython 3.14):
https://github.com/python/cpython/blob/3.14/Modules/pyexpat.c#L439-L443
Remove `@unittest.expectedFailure` from tests that now pass
(23 in test_xml_etree, 15 in test_minidom, 1 in test_regrtest).
Assisted-by: Claude:claude-opus-4-8
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
