[libc++][format] Removes an AIX work-around.

[Mordante]

Summary

This work-around was for Clang 13 and older, which we no longer support.

[ldionne]

Nice, thanks for the cleanup!

libcxx/include/__format/format_functions.h

 private:
   basic_string_view<_CharT> __str_;
 
   using _Context = __format::__compile_time_basic_format_context<_CharT>;
 
   static constexpr array<__format::__arg_t, sizeof...(_Args)> __types_{
       __format::__determine_arg_t<_Context, remove_cvref_t<_Args>>()...};
 
-  // TODO FMT remove this work-around when the AIX ICE has been resolved.
-#    if defined(_AIX) && defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1400
-  template <class _Tp>
-  static constexpr __format::__compile_time_handle<_CharT> __get_handle() {
-    __format::__compile_time_handle<_CharT> __handle;
-    if (__format::__determine_arg_t<_Context, _Tp>() == __format::__arg_t::__handle)
-      __handle.template __enable<_Tp>();
-
-    return __handle;
-  }
-
-  static constexpr array<__format::__compile_time_handle<_CharT>, sizeof...(_Args)> __handles_{
-      __get_handle<_Args>()...};
-#    else
   static constexpr array<__format::__compile_time_handle<_CharT>, sizeof...(_Args)> __handles_{[] {
     using _Tp = remove_cvref_t<_Args>;
     __format::__compile_time_handle<_CharT> __handle;
     if (__format::__determine_arg_t<_Context, _Tp>() == __format::__arg_t::__handle)
       __handle.template __enable<_Tp>();
 
     return __handle;
   }()...};
-#    endif
 };
 
 template <class... _Args>
 using format_string = basic_format_string<char, type_identity_t<_Args>...>;
 
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 template <class... _Args>
 using wformat_string = basic_format_string<wchar_t, type_identity_t<_Args>...>;