Refactor check_multiple_input_output and add GPU test
Refactor check_multiple_input_output and add GPU test

niboshi/chainer,hvy/chainer,jnishi/chainer,chainer/chainer,ktnyt/chainer,keisuke-umezawa/chainer,ronekko/chainer,keisuke-umezawa/chainer,tkerola/chainer,ktnyt/chainer,kashif/chainer,wkentaro/chainer,chainer/chainer,wkentaro/chainer,wkentaro/chainer,hvy/chainer,ktnyt/chainer,jnishi/chainer,chainer/chainer,wkentaro/chainer,keisuke-umezawa/chainer,ktnyt/chainer,pfnet/chainer,niboshi/chainer,keisuke-umezawa/chainer,niboshi/chainer,hvy/chainer,chainer/chainer,okuta/chainer,jnishi/chainer,rezoo/chainer,hvy/chainer,okuta/chainer,okuta/chainer,anaruse/chainer,okuta/chainer,jnishi/chainer,aonotas/chainer,niboshi/chainer