arm64: Implement Icmp for I16X8 and I32X4

Copyright (c) 2020, Arm Limited.

cranelift/codegen/src/isa/aarch64/inst/regs.rs

@@ -320,12 +320,12 @@ pub fn show_vreg_vector(reg: Reg, mb_rru: Option<&RealRegUniverse>, ty: Type) ->
 
     match ty {
         I8X16 => s.push_str(".16b"),
+        I16X8 => s.push_str(".8h"),
+        I32X4 => s.push_str(".4s"),
         F32X2 => s.push_str(".2s"),
         I8X8 => s.push_str(".8b"),
         I16X4 => s.push_str(".4h"),
-        I16X8 => s.push_str(".8h"),
         I32X2 => s.push_str(".2s"),
-        I32X4 => s.push_str(".4s"),
         I64X2 => s.push_str(".2d"),
         _ => unimplemented!(),
     }