Update release notes to 17.0.8.1+1
Add backport of JDK-8312489 already upstream in 17.0.10 (see OPENJDK-2095)
Update openjdk_news script to specify subdirectory last
Add missing discover_trees script required by openjdk_news
Synchronise runtime and buildtime tzdata requirements
Resolves: rhbz#2236592
