[clang] [clang][FMV] Do not omit explicit default target_version attribute. (PR #96628)

[Pavel Iliin via cfe-commits]

https://github.com/ilinpv approved this pull request.

Look good, thanks for refactoring and removing obsolete checks after FMV changes related to ordering and default version.

https://github.com/llvm/llvm-project/pull/96628