test: remove timer in fs.watchFile() test

The timer was there to address a race condition that has been removed
from the test. Remove it.

PR-URL: #21694
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>

Author: Trott

test/parallel/test-fs-watch-file-enoent-after-deletion.js

@@ -45,4 +45,4 @@ fs.watchFile(filename, { interval: 50 }, common.mustCall(function(curr, prev) {
   fs.unwatchFile(filename);
 }));
 
-setTimeout(fs.unlinkSync, common.platformTimeout(300), filename);
+fs.unlinkSync(filename);