[llvm] [SystemZ] Handle IR struct arguments correctly. (PR #169583)

[Jonas Paulsson via llvm-commits]

JonPsson1 wrote:

> The fun9 does look broken to me ... Can you verify how plain i72 types are (passed and) returned currently?

It seems it works just the same with i72 as with {i72} in this test, both on main and with this branch.

https://github.com/llvm/llvm-project/pull/169583