gh-109017: Use non alternate name for Kyiv (GH-109251)

tzdata provides Kiev as an alternative to Kyiv:
https://sources.debian.org/src/tzdata/2023c-10/backward/?hl=314#L314

But Debian moved it to the tzdata-legacy package breaking the test:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1050530

This patch switches to the name provided by tzdata.

Also check that the new name is actually available.