[llvm] [DirectX] Infrastructure to collect shader flags for each function (PR #112967)

[Chris B via llvm-commits]

https://github.com/llvm-beanz commented:

Something I'm also just noticing. It doesn't look like any of the tests here actually trigger the errors. Should these even be errors? Should they instead be asserts?

https://github.com/llvm/llvm-project/pull/112967