Fix incorrect handling of dirfd in os.symlink

- changed tests to also run in real OS
- work in progress

pyfakefs/fake_os.py

@@ -1162,12 +1162,12 @@ def symlink(
             dst: Path to the symlink to create.
             target_is_directory: Currently ignored.
             dir_fd: If not `None`, the file descriptor of a directory,
-                with `src` being relative to this directory.
+                with `dst` being relative to this directory.
 
         Raises:
             OSError:  if the file already exists.
         """
-        src = self._path_with_dir_fd(src, self.symlink, dir_fd)
+        dst = self._path_with_dir_fd(dst, self.symlink, dir_fd)
         self.filesystem.create_symlink(dst, src, create_missing_dirs=False)
 
     def link(
@@ -1178,7 +1178,7 @@ def link(
         src_dir_fd: Optional[int] = None,
         dst_dir_fd: Optional[int] = None,
     ) -> None:
-        """Create a hard link at new_path, pointing at old_path.
+        """Create a hard link at dst, pointing at src.
 
         Args:
             src: An existing path to the target file.