Function safe_arch::truncate_m128d_to_m128i

#[must_use]pub fn truncate_m128d_to_m128i(a: m128d) -> m128i

This is supported with target feature sse2 only.

Truncate the f64 lanes to the lower i32 lanes (upper i32 lanes 0).

let a = m128d::from_array([1.1, 2.6]);
let b = truncate_m128d_to_m128i(a);
assert_eq!(<[i32; 4]>::from(b), [1, 2, 0, 0]);