* update layer_norm_cn.rst, test=develop

* update code for layer_norm_cn.rst, test=develop

* update LayerNorm_cn.rst layer_norm_cn.rst, test=develop

* update BatchNorm_cn.rst, GroupNorm_cn.rst, SpectralNorm_cn.rst, test=develop

* fix bug for GroupNorm, test=develop

* fix norm op, test=develop

* add comment, test=develop

* add comment for dygraph layer, test=develop

* add comment for dygraph layer, test=develop

* add comment for dygraph layer, test=develop

* add comment for name, test=develop