Format file path (#17280)
Format file path (#17280)

The parameter dirpath will be passed directly to c++ operater. The file address format will be different under win and UNIX.
tensor-tang/Paddle,tensor-tang/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,chengduoZH/Paddle,luotao1/Paddle,chengduoZH/Paddle,tensor-tang/Paddle,chengduoZH/Paddle,chengduoZH/Paddle,luotao1/Paddle,tensor-tang/Paddle,tensor-tang/Paddle,luotao1/Paddle,PaddlePaddle/Paddle