Update Twig from 1.35.0 to 1.42.4 (PHP 5.5 is now required!)

This fixes some errors on PHP 7.4 and contains even more fixes
Also bumped PHP version to 5.5 as Twig requires it.

system/libs/Twig/Twig/Test.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+@trigger_error('The Twig_Test class is deprecated since version 1.12 and will be removed in 2.0. Use \Twig\TwigTest instead.', E_USER_DEPRECATED);
+
+/**
+ * Represents a template test.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @deprecated since 1.12 (to be removed in 2.0)
+ */
+abstract class Twig_Test implements Twig_TestInterface, Twig_TestCallableInterface
+{
+    protected $options;
+    protected $arguments = [];
+
+    public function __construct(array $options = [])
+    {
+        $this->options = array_merge([
+            'callable' => null,
+        ], $options);
+    }
+
+    public function getCallable()
+    {
+        return $this->options['callable'];
+    }
+}