simplify simd_ty, simd_m_ty macros: do not repeat the element type N times

Author: RalfJung

crates/core_arch/src/aarch64/neon/mod.rs

@@ -3736,7 +3736,7 @@ mod tests {
         let b = i8x16::new(
             17, 18, 19, 20, 20, 21, 22, 23, 24, 25, 26, 27, 29, 29, 30, 31,
         );
-        let r = i8x16(1, 5, 9, 13, 17, 21, 25, 29, 35, 39, 41, 45, 49, 53, 58, 61);
+        let r = i8x16::new(1, 5, 9, 13, 17, 21, 25, 29, 35, 39, 41, 45, 49, 53, 58, 61);
         let e: i8x16 = transmute(vpaddq_u8(transmute(a), transmute(b)));
         assert_eq!(r, e);
     }