[clang] [HLSL] Add Texture3D and RWTexture3D types (PR #220438)

[Finn Plummer via cfe-commits]

================
@@ -322,6 +322,13 @@ static const TextureTypeInfo TextureTypes[] = {
      /*IsArray=*/false, /*IsROV=*/false,
      TemplateShape::ElementTypeAndSampleCount,
      TexCap::LoadMS | TexCap::Subscript},
+    {"Texture3D", ResourceClass::SRV, ResourceDimension::Dim3D,
+     /*IsArray=*/false, /*IsROV=*/false, TemplateShape::ElementType,
+     TexCap::Load | TexCap::Subscript | TexCap::Mips | TexCap::Sample |
+         TexCap::CalcLOD | TexCap::GetDims},
+    {"RWTexture3D", ResourceClass::UAV, ResourceDimension::Dim3D,
+     /*IsArray=*/false, /*IsROV=*/false, TemplateShape::ElementType,
+     TexCap::LoadRW | TexCap::Subscript | TexCap::GetDims},
----------------
inbelic wrote:

It seems like from [`HLSLBuiltinTypeDeclBuilder.cpp`](https://github.com/llvm/llvm-project/blob/173a02c755bf91fecf90ac4df972128baea91da8/clang/lib/Sema/HLSLBuiltinTypeDeclBuilder.cpp#L2214) that the `GetDimension` methods are not actually currently supported for 3D texture types? Is that planned to be addressed in another pr?

Locally I get:
```
    error: no member named 'GetDimensions' in 'hlsl::Texture3D<>'
    error: no member named 'GetDimensions' in 'hlsl::RWTexture3D<>'
```

https://github.com/llvm/llvm-project/pull/220438