[clang] [clang] remove ClassScopeFunctionSpecializationDecl (PR #66636)

[Aaron Ballman via cfe-commits]

================
@@ -9354,13 +9353,14 @@ Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
   }
   F.done();
 
+  bool isFriend = FD->getFriendObjectKind() != Decl::FOK_None;
----------------
AaronBallman wrote:

```suggestion
  bool IsFriend = FD->getFriendObjectKind() != Decl::FOK_None;
```
nit for naming style.

https://github.com/llvm/llvm-project/pull/66636