[3.11] gh-106242: Make ntpath.realpath errors consistent with abspath when there are embedded nulls (GH-108248)

gh-106242: Make ntpath.realpath errors consistent with abspath when there are embedded nulls (GH-108248)

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(cherry picked from commit de33b5c662ea8d35d81ed857c6a39e34ab94c510)

Co-authored-by: Steve Dower <steve.dower@python.org>
Co-authored-by: Gregory P. Smith <greg@krypto.org>