gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293)

Due to a bug, some Unicode codepoint attributes were considered
for characters not yet defined in Unicode 3.2.0 or attributes
which changed in later Unicode versions. RFC 3454 (StringPrep)
requires using Unicode 3.2.0 strictly.


Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com>
Co-authored-by: Petr Viktorin <encukou@gmail.com>