[5.4] Modify redirect with input to return empty if given empty array (…

…#17979)

* Modify redirect with input to return empty if given empty array

* Update RedirectResponse.php

src/Illuminate/Http/RedirectResponse.php

@@ -74,7 +74,7 @@ public function withCookies(array $cookies)
     public function withInput(array $input = null)
     {
         $this->session->flashInput($this->removeFilesFromInput(
-            $input ?: $this->request->input()
+            ! is_null($input) ? $input : $this->request->input()
         ));
 
         return $this;