test: minor refactoring of onticketkeycallback

The motivation for this commit is to make the the onticketkeycallback
function more readable.

PR-URL: #24718
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-https-resume-after-renew.js

@@ -22,16 +22,13 @@ const hmac = Buffer.alloc(16, 'H');
 
 server._sharedCreds.context.enableTicketKeyCallback();
 server._sharedCreds.context.onticketkeycallback = function(name, iv, enc) {
-  let newName, newIV;
   if (enc) {
-    newName = Buffer.alloc(16, 'A');
-    newIV = crypto.randomBytes(16);
-  } else {
-    // Renew
-    return [ 2, hmac, aes ];
+    const newName = Buffer.alloc(16, 'A');
+    const newIV = crypto.randomBytes(16);
+    return [ 1, hmac, aes, newName, newIV ];
   }
-
-  return [ 1, hmac, aes, newName, newIV ];
+  // Renew
+  return [ 2, hmac, aes ];
 };
 
 server.listen(0, function() {