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

[Finn Plummer via cfe-commits]

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@@ -50,6 +59,9 @@ void main(COORD_TYPE uv) {
   Tex.SampleBias(Samp, uv, 0.0f);
   // expected-error-re at +1 {{no member named 'SampleGrad' in 'hlsl::{{.*}}Texture}}
   Tex.SampleGrad(Samp, uv, (GRAD_TYPE)0, (GRAD_TYPE)0);
+#endif
+
+#ifndef HAS_SAMPLE_CMP
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inbelic wrote:

Follow-up to the HLSLExternalSemaSource comment: this file has no GetDimensions
section, so nothing catches the fact that `TexCap::GetDims` produces no methods for
Texture3D/RWTexture3D

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