[clang] [ItaniumCXXABI] Mark RTTI type name as global unnamed_addr (PR #111343)

[Richard Smith via cfe-commits]

zygoloid wrote:

https://itanium-cxx-abi.github.io/cxx-abi/abi.html#vague-rtti and https://itanium-cxx-abi.github.io/cxx-abi/abi.html#typeid in the ABI require the type name string to be globally unique, and some `std::type_info` implementations rely on that. You might be able to do this for some specific targets that choose a different ABI rule, but not in general.

https://github.com/llvm/llvm-project/pull/111343