[clang] `__noop` not marked as constexpr #102064 (PR #105983)

[Aaron Ballman via cfe-commits]

================
@@ -861,6 +861,8 @@ Bug Fixes to Compiler Builtins
 - Clang now allows pointee types of atomic builtin arguments to be complete template types
   that was not instantiated elsewhere.
 
+- Fix ``__noop`` not marked as constexpr. (#GH102064)
----------------
AaronBallman wrote:

```suggestion
- ``__noop` can now be used in a constant expression. (#GH102064)
```

https://github.com/llvm/llvm-project/pull/105983