[llvm] Implement areInlineCompatible for SystemZ using feature bitset (PR #132976)

[Ulrich Weigand via llvm-commits]

uweigand wrote:

Can you please fix the formatting issues clang-format has complained about?   Also, maybe expand the comment to say that we're currently only supporting identical feature sets, but that restriction should be relaxed in the future. Otherwise, this looks good.

https://github.com/llvm/llvm-project/pull/132976