message: minor fix to omp sorting tests
diff: @@ -335,6 +335,7 @@ TEST_F(Fbcsr, SortSortedMatrixIsEquivalentToRef)
  dmtx->sort_by_column_index();
  GKO_ASSERT_MTX_NEAR(mtx, dmtx, 0);
  + ASSERT_TRUE(dmtx->is_sorted_by_column_index());
  }
  @@ -346,6 +347,7 @@ TEST_F(Fbcsr, SortUnsortedMatrixIsEquivalentToRef)
  uns_mtx.omp->sort_by_column_index();
  GKO_ASSERT_MTX_NEAR(uns_mtx.ref, uns_mtx.omp, 0);
  + ASSERT_TRUE(uns_mtx.omp->is_sorted_by_column_index());
  }
  