message: improve jacobi test output
diff: @@ -578,13 +578,8 @@ TEST_F(Jacobi, SelectsTheSamePrecisionsAsRef)
  auto bj = bj_factory->generate(mtx);
  auto d_bj = gko::clone(ref, d_bj_factory->generate(mtx));
  - auto bj_prec =
  - bj->get_parameters().storage_optimization.block_wise.get_const_data();
  - auto d_bj_prec =
  - d_bj->get_parameters().storage_optimization.block_wise.get_const_data();
  - for (int i = 0; i < gko::as<Bj>(bj.get())->get_num_blocks(); ++i) {
  - EXPECT_EQ(bj_prec[i], d_bj_prec[i]);
  - }
  + GKO_ASSERT_ARRAY_EQ(bj->get_parameters().storage_optimization.block_wise,
  + d_bj->get_parameters().storage_optimization.block_wise);
  }
  