Function i32x4_extmul_low_u16x8

#[target_feature(enable = "simd128")]
pub fn i32x4_extmul_low_u16x8(a: v128, b: v128) -> v128

Lane-wise integer extended multiplication producing twice wider result than the inputs.

Equivalent of i32x4_mul(i32x4_extend_low_u16x8(a), i32x4_extend_low_u16x8(b))