[clang] [CIR] Upstream initial support for fixed size VectorType (PR #136488)

[Henrich Lauko via cfe-commits]

================
@@ -307,6 +307,26 @@ def CIR_ArrayType : CIR_Type<"Array", "array",
   }];
 }
 
+//===----------------------------------------------------------------------===//
+// VectorType (fixed size)
+//===----------------------------------------------------------------------===//
+
+def CIR_VectorType : CIR_Type<"Vector", "vector",
----------------
xlauko wrote:

Add missing changes from upstream, specifically custom builders.
```
  let builders = [
    TypeBuilderWithInferredContext<(ins
      "mlir::Type":$eltType, "uint64_t":$size
    ), [{
        return $_get(eltType.getContext(), eltType, size);
    }]>,
  ];
```

https://github.com/llvm/llvm-project/pull/136488