test: change callback function to arrow function

PR-URL: #24419
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Ouyang Yadong <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

test/parallel/test-zlib-invalid-input.js

@@ -43,7 +43,7 @@ const unzips = [
 
 nonStringInputs.forEach(common.mustCall((input) => {
   // zlib.gunzip should not throw an error when called with bad input.
-  zlib.gunzip(input, function(err, buffer) {
+  zlib.gunzip(input, (err, buffer) => {
     // zlib.gunzip should pass the error to the callback.
     assert.ok(err);
   });