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/Node/CheckToStringNode.php

@@ -0,0 +1,42 @@
+<?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.
+ */
+
+namespace Twig\Node;
+
+use Twig\Compiler;
+use Twig\Node\Expression\AbstractExpression;
+
+/**
+ * Checks if casting an expression to __toString() is allowed by the sandbox.
+ *
+ * For instance, when there is a simple Print statement, like {{ article }},
+ * and if the sandbox is enabled, we need to check that the __toString()
+ * method is allowed if 'article' is an object. The same goes for {{ article|upper }}
+ * or {{ random(article) }}
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class CheckToStringNode extends AbstractExpression
+{
+    public function __construct(AbstractExpression $expr)
+    {
+        parent::__construct(['expr' => $expr], [], $expr->getTemplateLine(), $expr->getNodeTag());
+    }
+
+    public function compile(Compiler $compiler)
+    {
+        $compiler
+            ->raw('$this->sandbox->ensureToStringAllowed(')
+            ->subcompile($this->getNode('expr'))
+            ->raw(')')
+        ;
+    }
+}