util added result

Author: mertcanaltin

lib/internal/mime.js

@@ -24,6 +24,7 @@ const START_ENDING_WHITESPACE = /[\r\n\t ]*$/;
 
 function toASCIILower(str) {
   if (!/[^\x00-\x7f]/.test(str)) return StringPrototypeToLowerCase(str);
+  let result = '';
   for (let i = 0; i < str.length; i++) {
     const char = str[i];