Function safe_arch::floor_m128d_s

#[must_use]pub fn floor_m128d_s(a: m128d, b: m128d) -> m128d

This is supported with target feature sse4.1 only.

Round the low lane of b toward negative infinity, high lane is a.

let a = m128d::from_array([-0.1, 1.8]);
let b = m128d::from_array([2.5, 3.0]);
assert_eq!(floor_m128d_s(a, b).to_array(), [2.0, 1.8]);