Function allow_move_dir_over_non_empty_dir

cpp/src/arrow/filesystem/test_util.h:180–180

- Whether the filesystem allows moving a directory "over" a non-empty destination

  virtual bool allow_move_dir() const { return true; }
  // - Whether the filesystem allows moving a directory "over" a non-empty destination
  virtual bool allow_move_dir_over_non_empty_dir() const { return false; }
  // - Whether the filesystem allows appending to a file
  virtual bool allow_append_to_file() const { return true; }
  // - Whether the filesystem allows appending to a nonexistent file