Fixing Windows ARM64 support

Author: lemire

src/is_utf8.cpp

@@ -529,22 +529,12 @@ static inline uint32_t detect_supported_architectures() {
   return instruction_set::ALTIVEC;
 }
 
-#elif defined(__arm__) || defined(__aarch64__) // incl. armel, armhf, arm64
-
-#if defined(__ARM_NEON)
+#elif defined(__aarch64__) || defined(_M_ARM64)
 
 static inline uint32_t detect_supported_architectures() {
   return instruction_set::NEON;
 }
 
-#else // ARM without NEON
-
-static inline uint32_t detect_supported_architectures() {
-  return instruction_set::DEFAULT;
-}
-
-#endif
-
 #elif defined(__x86_64__) || defined(_M_AMD64) // x64
 
 namespace {