test_runner: fixed test shorthands return type

`test.todo`, `test.only` and `test.skip` are expected to return the
same as `test`. This commit corrects the inconsistent behavior of
these shorthands.

Fixes: nodejs#48557

lib/internal/test_runner/harness.js

@@ -216,9 +216,7 @@ function runInParentContext(Factory) {
 
   const test = (name, options, fn) => run(name, options, fn);
   ArrayPrototypeForEach(['skip', 'todo', 'only'], (keyword) => {
-    test[keyword] = (name, options, fn) => {
-      run(name, options, fn, { [keyword]: true });
-    };
+    test[keyword] = (name, options, fn) => run(name, options, fn, { [keyword]: true });
   });
   return test;
 }