Merge branch '4.4' into 5.0

* 4.4: (27 commits)
  [Serializer] minor cleanup
  fix merge
  Run PHP 8 as 7.4.99
  Remove calls to deprecated ReflectionParameter::getClass().
  [VarDumper] fix PHP 8 support
  Add php 8 to travis.
  [Cache] Accessing undefined constants raises an Error in php8
  [Cache] allow DBAL v3
  Skip Doctrine DBAL on php 8 until we have a compatible version.
  [DomCrawler] Catch expected ValueError.
  Made method signatures compatible with their corresponding traits.
  [ErrorHandler] Apply php8 fixes from Debug component.
  [DomCrawler] Catch expected ValueError.
  [Validator] Catch expected ValueError.
  [VarDumper] ReflectionFunction::isDisabled() is deprecated.
  [BrowserKit] Raw body with custom Content-Type header
  [PropertyAccess] Parse php 8 TypeErrors correctly.
  [Intl] Fix call to ReflectionProperty::getValue() for static properties.
  [HttpKernel] Prevent calling method_exists() with non-string values.
  Fix wrong roles comparison
  ...

Author: nicolas-grekas

File/UploadedFile.php

@@ -31,7 +31,7 @@
  */
 class UploadedFile extends File
 {
-    private $test = false;
+    private $test;
     private $originalName;
     private $mimeType;
     private $error;
@@ -76,7 +76,7 @@ public function __construct(string $path, string $originalName, string $mimeType
      * It is extracted from the request from which the file has been uploaded.
      * Then it should not be considered as a safe value.
      *
-     * @return string|null The original name
+     * @return string The original name
      */
     public function getClientOriginalName()
     {
@@ -105,7 +105,7 @@ public function getClientOriginalExtension()
      * For a trusted mime type, use getMimeType() instead (which guesses the mime
      * type based on the file content).
      *
-     * @return string|null The mime type
+     * @return string The mime type
      *
      * @see getMimeType()
      */