[clang] [APINotes] Add a mechanism to ignore API notes after a certain SDK version (PR #226041)

[Ian Anderson via cfe-commits]

ian-twilightcoder wrote:

@j-hui came up with a 3rd solution: Have Swift put the expiring API notes in different directories and then conditionally pass those `-iapinotes-modules` in the ClangImporter. I like that solution a lot, it doesn't involve any Clang changes at all and is a clean change in Swift.

https://github.com/llvm/llvm-project/pull/226041