message: XLA Dropout Op Fix
  Summary:
  XLA Dropout Op Fix
  Ref: T18496
  Test Plan: Compiles
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, georgep, hakons
  Subscribers: hakons
  Maniphest Tasks: T18496
diff: @@ -119,8 +119,9 @@ class DropoutOp : public PoplarOpDef {
  // Pull out noise_shape if it is set. At this point it is a std::vector,
  // but poprand::dropout expects a poplar::Tensor*
  // noise_shape becomes a constant tensor residing on tile 0.
  - const Shape ns_ref_shape = ShapeUtil::MakeShape(
  - output_shape.element_type(), dropout_instruction->NoiseShape());
  + const Shape ns_ref_shape =
  + ShapeUtil::MakeShape(inst->operand(0)->shape().element_type(),
  + dropout_instruction->NoiseShape());
  TF_ASSIGN_OR_RETURN(poplar::Tensor reference,
  AddPlainTensor(graph, debug_name + "/ShapedReference",
  ns_ref_shape, res, false));
  