message: Add half support in op registration.
  No implmentation yet due to Windows breakage.
diff: @@ -1421,7 +1421,7 @@ REGISTER_OP("Range")
  .Input("limit: Tidx")
  .Input("delta: Tidx")
  .Output("output: Tidx")
  - .Attr("Tidx: {bfloat16, float, double, int32, int64} = DT_INT32")
  + .Attr("Tidx: {bfloat16, half, float, double, int32, int64} = DT_INT32")
  .SetShapeFn([](InferenceContext* c) {
  ShapeHandle unused;
  TF_RETURN_WITH_CONTEXT_IF_ERROR(c->WithRank(c->input(0), 0, &unused),
  @@ -1460,7 +1460,7 @@ REGISTER_OP("LinSpace")
  .Input("stop: T")
  .Input("num: Tidx")
  .Output("output: T")
  - .Attr("T: {bfloat16, float, double}")
  + .Attr("T: {bfloat16, half, float, double}")
  .Attr("Tidx: {int32, int64} = DT_INT32")
  .SetShapeFn([](InferenceContext* c) {
  ShapeHandle unused;
  