Function safe_arch::truncate_m128_to_m128i

#[must_use]pub fn truncate_m128_to_m128i(a: m128) -> m128i

This is supported with target feature sse2 only.

Truncate the f32 lanes to i32 lanes.

let a = m128::from_array([1.1, 2.6, 3.5, 4.0]);
let b = truncate_m128_to_m128i(a);
assert_eq!(<[i32; 4]>::from(b), [1, 2, 3, 4]);