Merge branch '4.4'

* 4.4:
  some backports from master
  Add return types to internal|final|private methods
  [HttpFoundation] Precalculate session expiry timestamp

Author: nicolas-grekas

FormFieldRegistry.php

@@ -90,7 +90,7 @@ public function &get(string $name)
      *
      * @return bool Whether the form has the given field
      */
-    public function has(string $name)
+    public function has(string $name): bool
     {
         try {
             $this->get($name);
@@ -128,7 +128,7 @@ public function set(string $name, $value)
      *
      * @return FormField[] The list of fields as [string] Fully qualified name => (mixed) value)
      */
-    public function all()
+    public function all(): array
     {
         return $this->walk($this->fields, $this->base);
     }