Revert "DRY up the kernel for amsgrad"
Revert "DRY up the kernel for amsgrad"

This reverts commit a126540f42f547f6170dfad770f7a6df84efea66.

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