[libc++][format][nfc] Remove dead code.

This was an early part of the prototype. This has never been shipped
enabled and the final version of this code looks completely different.

GitOrigin-RevId: 0e50216f22adef2d69cc35ae0e246a42c9a7458c
diff --git a/include/format b/include/format
index ce16857..53ecb5a 100644
--- a/include/format
+++ b/include/format
@@ -350,78 +350,6 @@
 
 namespace __format {
 
-template <class _Tp, class _CharT>
-requires(is_arithmetic_v<_Tp> &&
-         !same_as<_Tp, bool>) struct _LIBCPP_HIDE_FROM_ABI
-    __formatter_arithmetic {
-  _LIBCPP_HIDE_FROM_ABI
-  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
-    // TODO FMT Implement
-    return __parse_ctx.begin();
-  }
-
-  _LIBCPP_HIDE_FROM_ABI
-  auto format(_Tp __value, auto& __ctx) -> decltype(__ctx.out()) {
-    return __handle_format(__value, __ctx);
-  }
-
-private:
-  template <class _Uv>
-  _LIBCPP_HIDDEN static string
-  __convert(_Uv __value) requires(same_as<_CharT, char>) {
-    return _VSTD::to_string(__value);
-  }
-#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-  template <class _Uv>
-  _LIBCPP_HIDDEN static wstring
-  __convert(_Uv __value) requires(same_as<_CharT, wchar_t>) {
-    return _VSTD::to_wstring(__value);
-  }
-#endif
-
-  template <class _Uv>
-  _LIBCPP_HIDDEN auto __handle_format(_Uv __value, auto& __ctx)
-      -> decltype(__ctx.out())
-  {
-    // TODO FMT Implement using formatting arguments
-    // TODO FMT Improve PoC since using std::to_string is inefficient.
-    // Note the code doesn't use std::string::iterator since the unit tests
-    // test with debug iterators and they fail with strings created from
-    // std::to_string.
-    auto __str = __convert(__value);
-    auto __out_it = __ctx.out();
-    for (size_t __i = 0, __e = __str.size(); __i != __e; ++__i)
-      *__out_it++ = __str[__i];
-    return __out_it;
-  }
-};
-} // namespace __format
-
-// These specializations are helper stubs and not proper formatters.
-// TODO FMT Implement the proper formatter specializations.
-
-// Floating point types.
-// TODO FMT There are no replacements for the floating point stubs due to not
-// having floating point support in std::to_chars yet. These stubs aren't
-// removed since they are useful for developing the real versions.
-// Ultimately the stubs should be implemented properly and this code can be
-// removed.
-#if 0
-template <class _CharT>
-struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<float, _CharT>
-    : public __format::__formatter_arithmetic<float, _CharT> {};
-template <class _CharT>
-struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
-    formatter<double, _CharT>
-    : public __format::__formatter_arithmetic<double, _CharT> {};
-template <class _CharT>
-struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
-    formatter<long double, _CharT>
-    : public __format::__formatter_arithmetic<long double, _CharT> {};
-#endif
-
-namespace __format {
-
 template <class _CharT, class _ParseCtx, class _Ctx>
 _LIBCPP_HIDE_FROM_ABI const _CharT*
 __handle_replacement_field(const _CharT* __begin, const _CharT* __end,