keep doctest compatible with Unicode 15.1 Revert changes made in https://github.com/fonttools/fonttools/commit/10a61ef7de0f5c99f37584840641ee6c62dc74bd before Debian packages support for unicode 16.0.
Disable new tests related to unicode 16.0 Do not run tests introduced by https://github.com/fonttools/fonttools/commit/b26271cc4dcc5256a2181d8307dde9a2b3cd45d5 before using Unicode 16.0.