message: Fix a small bug in the mat-gen tests.
diff: @@ -55,7 +55,7 @@ protected:
  4, 3, true, std::normal_distribution<double>(50, 5),
  std::normal_distribution<double>(20.0, 5.0), std::ranlux48(42),
  exec)),
  - u_mtx(gko::test::generate_random_lower_triangular_matrix(
  + u_mtx(gko::test::generate_random_upper_triangular_matrix(
  3, 4, true, std::normal_distribution<double>(50, 5),
  std::normal_distribution<double>(20.0, 5.0), std::ranlux48(42),
  exec)),
  