Function safe_arch::set_i64_m128i_s

#[must_use]pub fn set_i64_m128i_s(i: i64) -> m128i

This is supported with target feature sse2 only.

Set an i64 as the low 64-bit lane of an m128i, other lanes blank.

let a: [i64; 2] = set_i64_m128i_s(1_i64).into();
let b: [i64; 2] = m128i::from([1_i64, 0]).into();
assert_eq!(a, b);