Implementing `tbuffer` layout(s) (#4436)

* Implementing `tbuffer` layouts.

1. Add to layout options 'TextureBuffer' layouts.
2. Add on to existing logic a way to allocate appropriate registers for TextureBufferType (this was made to work with parameter block logic).
3. Added asserts so objects missing a layout will gracefully crash

This means `tbuffer` now works for hlsl,glsl,metal targets, spirv has yet to implement logic for `TextureBufferType`.

* disable metal tests and fix emitting code a bit

fixing the emitting code means metal compilation emits a useful error (help point users/developers to #4435)

* fix warning

1 files changed, 7 insertions, 0 deletions

diff --git a/source/slang/slang-emit-metal.cpp b/source/slang/slang-emit-metal.cpp
index 07d5b9f6c..0a5506776 100644
--- a/source/slang/slang-emit-metal.cpp
+++ b/source/slang/slang-emit-metal.cpp
@@ -690,6 +690,13 @@ void MetalSourceEmitter::emitSimpleTypeImpl(IRType* type)
         _emitHLSLTextureType(texType);
         return;
     }
+    else if (as<IRTextureBufferType>(type))
+    {
+        m_writer->emit("texture_buffer<");
+        emitVal(type->getOperand(0), getInfo(EmitOp::General));
+        m_writer->emit(">");
+        return;
+    }
     else if (auto imageType = as<IRGLSLImageType>(type))
     {
         _emitHLSLTextureType(imageType);