[clang] [HLSL] Add __is_scalarized_layout_compatible (PR #102227)

[Aaron Ballman via cfe-commits]

================
@@ -658,6 +658,9 @@ KEYWORD(out                         , KEYHLSL)
 #define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId) KEYWORD(Name, KEYHLSL)
 #include "clang/Basic/HLSLIntangibleTypes.def"
 
+// HLSL Type traits.
+TYPE_TRAIT_2(__is_scalarized_layout_compatible, IsScalarizedLayoutCompatible, KEYHLSL)
----------------
AaronBallman wrote:

Can you prefix this with `__builtin_`? We have bad experiences with accidental naming conflicts (not that I think this will run into it), and we're starting to add a prefix now to help avoid that.

https://github.com/llvm/llvm-project/pull/102227