“f56f14929833b5211324d40a47216feca423b7a0”上不存在“paddle/fluid/framework/backward_test.cc”
* Chage `IndicateDataType` to `GetKernelType`. Make it easier to understand. * Change `OpKernelKey` to `OpKernelType` * Make operator developers can customize which kernel the operator will use in runtime.