[clang] [WinEH] Only emit err_seh_object_unwinding when CXXExceptions are enabled (PR #180959)

[via cfe-commits]

GkvJwa wrote:

> The change itself LGTM.
> 
> I still think "[WinEH] Only emit err_seh_object_unwinding when CXXExceptions are enabled" would be a clearer title.

thanks

https://github.com/llvm/llvm-project/pull/180959