Rewrite GetDeviceThreadSafe test using CheckThreadSafe()
Rewrite GetDeviceThreadSafe test using CheckThreadSafe()

okuta/chainer,jnishi/chainer,ktnyt/chainer,wkentaro/chainer,chainer/chainer,hvy/chainer,ktnyt/chainer,chainer/chainer,hvy/chainer,hvy/chainer,okuta/chainer,niboshi/chainer,okuta/chainer,niboshi/chainer,jnishi/chainer,keisuke-umezawa/chainer,chainer/chainer,jnishi/chainer,ktnyt/chainer,wkentaro/chainer,niboshi/chainer,hvy/chainer,tkerola/chainer,okuta/chainer,niboshi/chainer,chainer/chainer,keisuke-umezawa/chainer,ktnyt/chainer,keisuke-umezawa/chainer,jnishi/chainer,wkentaro/chainer,keisuke-umezawa/chainer,pfnet/chainer,wkentaro/chainer