message: Register a new Sum op for T:int64 and Tidx:int32
diff: @@ -76,7 +76,15 @@ REGISTER_KERNEL_BUILDER(
  .HostMemory("output")
  .HostMemory("reduction_indices"),
  ReductionOp<CPUDevice, int32, int64, Eigen::internal::SumReducer<int32>>);
  -
  +REGISTER_KERNEL_BUILDER(
  + Name("Sum")
  + .Device(DEVICE_GPU)
  + .TypeConstraint<int64>("T")
  + .TypeConstraint<int32>("Tidx")
  + .HostMemory("input")
  + .HostMemory("output")
  + .HostMemory("reduction_indices"),
  + ReductionOp<CPUDevice, int64, int32, Eigen::internal::SumReducer<int64>>);
  #endif
  #ifdef TENSORFLOW_USE_SYCL
  