[clang] [clang][CGObjC] Sign the v-table pointer in ObjC exception RTTI. (PR #135562)

[John McCall via cfe-commits]

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@@ -317,6 +317,7 @@ Non-comprehensive list of changes in this release
   ``sizeof`` or ``typeof`` expression. (#GH138444)
 - Deprecation warning is emitted for the deprecated ``__reference_binds_to_temporary`` intrinsic.
   ``__reference_constructs_from_temporary`` should be used instead. (#GH44056)
+- Support authenticated ``type_info`` vtable pointers in Objective-C++
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rjmccall wrote:

```suggestion
- Support pointer authentication for Objective-C exceptions
```

https://github.com/llvm/llvm-project/pull/135562