[libc++] Fix unnecessary fflush() in __vprint_unicode() on POSIX

Fixes #70142

Author: dimztimz

libcxx/include/print

@@ -230,15 +230,6 @@ __vprint_nonunicode(FILE* __stream, string_view __fmt, format_args __args, bool
 // terminal when the output is redirected. Typically during testing the
 // output is redirected to be able to capture it. This makes it hard to
 // test this code path.
-template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
-_LIBCPP_HIDE_FROM_ABI inline void
-__vprint_unicode_posix(FILE* __stream, string_view __fmt, format_args __args, bool __write_nl, bool __is_terminal) {
-  // TODO PRINT Should flush errors throw too?
-  if (__is_terminal)
-    std::fflush(__stream);
-
-  __print::__vprint_nonunicode(__stream, __fmt, __args, __write_nl);
-}
 
 #    ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
@@ -310,7 +301,7 @@ __vprint_unicode([[maybe_unused]] FILE* __stream,
   // Windows there is a different API. This API requires transcoding.
 
 #    ifndef _WIN32
-  __print::__vprint_unicode_posix(__stream, __fmt, __args, __write_nl, __print::__is_terminal(__stream));
+  __print::__vprint_nonunicode(__stream, __fmt, __args, __write_nl);
 #    elif !defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
   __print::__vprint_unicode_windows(__stream, __fmt, __args, __write_nl, __print::__is_terminal(__stream));
 #    else