message: Restrict pack rewrite to non-subtype types
  This rewrite on inputs with subtypes has some unexpected behavior that needs to be investigated.
diff: @@ -328,6 +328,10 @@ struct ConvertPackToReshape : public OpRewritePattern<PackOp> {
  return failure();
  }
  + // TODO(b/179286433): Follow up to verify behavior here and the user pass.
  + if (input_ty.getElementType().isa<TensorFlowTypeWithSubtype>())
  + return failure();
  +
  // Create constant shape for reshape.
  auto type =
  RankedTensorType::get(output_ty.getRank(), rewriter.getIntegerType(64));
  