Remove irrelevant info from `forward_op_nodes`
Remove irrelevant info from `forward_op_nodes`

hvy/chainer,niboshi/chainer,niboshi/chainer,chainer/chainer,niboshi/chainer,hvy/chainer,hvy/chainer,chainer/chainer,chainer/chainer,niboshi/chainer,pfnet/chainer,hvy/chainer,chainer/chainer