message: Remove eigen and old product implem from benches where they are slow
  It's been shown in the past that they are too slow, we need to keep
  acceptable bench times.
diff: @@ -105,18 +105,21 @@ fn bench_densities() -> Result<(), Box<dyn std::error::Error>> {
  1e-5, 2e-5, 5e-5, 1e-4, 2e-4,
  5e-4, //1e-3, 2e-3, 3e-3, 5e-3,
  ],
  + forbid_old: true,
  ..Default::default()
  },
  BenchSpec {
  shape: (150000, 25000),
  densities: vec![1e-7, 1e-6, 1e-5, 1e-4],
  forbid_old: true,
  + forbid_eigen: true,
  ..Default::default()
  },
  BenchSpec {
  shape: (150000, 250000),
  densities: vec![1e-7, 1e-6, 1e-5, 1e-4],
  forbid_old: true,
  + forbid_eigen: true,
  ..Default::default()
  },
  BenchSpec {
  @@ -131,6 +134,7 @@ fn bench_densities() -> Result<(), Box<dyn std::error::Error>> {
  (55000, 55000),
  ],
  nnz_over_rows: 4,
  + forbid_old: true,
  bench_filename: "sparse_mult_perf_by_shape.png".to_string(),
  ..Default::default()
  },
  