Using commands:
   glib/gen-unicode-tables.pl -both 12.0.0 path/to/UCD
   tests/gen-casefold-txt.py 12.0.0 path/to/UCD/CaseFolding.txt \
     > tests/casefold.txt
   tests/gen-casemap-txt.py 12.0.0 path/to/UCD/UnicodeData.txt \
      path/to/UCD/SpecialCasing.txt > tests/casemap.txt
plus some manual additions of the new G_UNICODE_SCRIPT_* symbols to
gunicode.h, guniprop.c and glib/tests/unicode.c.

Using UCD release https://www.unicode.org/Public/zipped/12.0.0/UCD.zip.
Signed-off-by: Philip Withnall <withnall@endlessm.com>

Fixes: #1713