Function safe_arch::get_f32_from_m128_s

#[must_use]pub fn get_f32_from_m128_s(a: m128) -> f32

This is supported with target feature sse only.

Gets the low lane as an individual f32 value.

let a = m128::from_array([1.0, 2.0, 3.0, 4.0]);
assert_eq!(1_f32, get_f32_from_m128_s(a));