[llvm] [DirectX] Make dx.RawBuffer an op that can't be replaced (PR #154620)

[Justin Bogner via llvm-commits]

bogner wrote:

> @bogner the new Verifier changes are causing CodeGenHLSL/builtins/hlsl_resource_t.hlsl to fail
specifically with the error:Function takes token but isn't an intrinsic

That's probably fine / expected - that test is creating the `__hlsl_resource_t` directly and calling functions on it, which isn't really meaningful. As far as I can tell the tests that use the actual HLSL types (RWBuffer/StructuredBuffer) are still okay. I guess the fix will be to add a wrapper struct:
```c++
struct CustomResource {
  handle_float_t h;
};
```
and have the functions in that test use the struct not the handle itself. @hekota does this sound right to you?

https://github.com/llvm/llvm-project/pull/154620