arm64: Implement Icmp for I16X8 and I32X4

Copyright (c) 2020, Arm Limited.

build.rs

@@ -182,6 +182,8 @@ fn ignore(testsuite: &str, testname: &str, strategy: &str) -> bool {
         "Cranelift" => match (testsuite, testname) {
             ("simd", "simd_i8x16_cmp") => return false,
             ("simd", "simd_store") => return false,
+            ("simd", "simd_i16x8_cmp") => return false,
+            ("simd", "simd_i32x4_cmp") => return false,
             // Most simd tests are known to fail on aarch64 for now, it's going
             // to be a big chunk of work to implement them all there!
             ("simd", _) if target.contains("aarch64") => return true,