message: Add black_box to benchmarking
diff: @@ -196,7 +196,7 @@ fn bench_metering(c: &mut Criterion) {
  let import_object = imports! {};
  let mut instance = module.instantiate(&import_object).unwrap();
  let add_to: Func<(i32, i32), i32> = instance.func("add_to").unwrap();
  - b.iter(|| add_to.call(100, 4).unwrap())
  + b.iter(|| black_box(add_to.call(100, 4)))
  })
  .with_function("Gas Metering", |b| {
  let compiler = get_compiler(0, false);
  @@ -209,7 +209,7 @@ fn bench_metering(c: &mut Criterion) {
  };
  let mut gas_instance = gas_module.instantiate(&gas_import_object).unwrap();
  let gas_add_to: Func<(i32, i32), i32> = gas_instance.func("add_to").unwrap();
  - b.iter(|| gas_add_to.call(100, 4).unwrap())
  + b.iter(|| black_box(gas_add_to.call(100, 4)))
  })
  .with_function("Built-in Metering", |b| {
  let metering_compiler = get_compiler(std::u64::MAX, true);
  @@ -221,7 +221,7 @@ fn bench_metering(c: &mut Criterion) {
  .unwrap();
  metering::set_points_used(&mut metering_instance, 0u64);
  let metering_add_to: Func<(i32, i32), i32> = metering_instance.func("add_to").unwrap();
  - b.iter(|| metering_add_to.call(100, 4).unwrap())
  + b.iter(|| black_box(metering_add_to.call(100, 4)))
  }),
  );
  }
  