[3.14] gh-83895: Accept input larger than 2 GiB in the C implementation of ElementTree (GH-156746) (GH-156772)
XMLParser.feed() and ElementTree.parse() raised OverflowError, because Expat
takes the length as an int. The data is now fed to Expat in chunks of 1 MiB,
as xml.parsers.expat does since bpo-17089, so the pure Python implementation
already accepted such input.
(cherry picked from commit 9259e8ba4de8e2f534d97233b8e0f9c2537691d3)