Change the way to handle built-in types in _concat_arrays
Change the way to handle built-in types in _concat_arrays

jnishi/chainer,wkentaro/chainer,kashif/chainer,hvy/chainer,ysekky/chainer,niboshi/chainer,kiyukuta/chainer,keisuke-umezawa/chainer,niboshi/chainer,cupy/cupy,ktnyt/chainer,ktnyt/chainer,rezoo/chainer,tkerola/chainer,niboshi/chainer,okuta/chainer,jnishi/chainer,chainer/chainer,wkentaro/chainer,wkentaro/chainer,keisuke-umezawa/chainer,niboshi/chainer,cupy/cupy,chainer/chainer,anaruse/chainer,hvy/chainer,hvy/chainer,ktnyt/chainer,chainer/chainer,okuta/chainer,cupy/cupy,jnishi/chainer,keisuke-umezawa/chainer,pfnet/chainer,delta2323/chainer,ktnyt/chainer,wkentaro/chainer,chainer/chainer,okuta/chainer,hvy/chainer,cupy/cupy,jnishi/chainer,aonotas/chainer,ronekko/chainer,okuta/chainer,keisuke-umezawa/chainer