[llvm] [DirectX] Implement the DXILCBufferAccess pass (PR #134571)

[Chris B via llvm-commits]

llvm-beanz wrote:

> I'm seeing a pretty large regression in the DML shaders that are able to compile in the form `Load of {{.*}} is not a global resource handle`.

The shaders failing to compile instead of compiling garbage is not a regression.

https://github.com/llvm/llvm-project/pull/134571