[llvm] [Offload] Refactor offload test requirements (PR #95196)

[via llvm-commits]

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

LGTM I think the overall simplification is nice (at least from the perspective of someone writing these on a fairly regular basis at least), but please do wait on one of the more experienced reviewers to approve before landing! They'll likely know the broader impact of simplifying the architecture listing, if there is any :-) 

https://github.com/llvm/llvm-project/pull/95196