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/TwigFunction.php

@@ -0,0 +1,118 @@
+<?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;
+
+use Twig\Node\Node;
+
+/**
+ * Represents a template function.
+ *
+ * @final
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class TwigFunction
+{
+    protected $name;
+    protected $callable;
+    protected $options;
+    protected $arguments = [];
+
+    public function __construct($name, $callable, array $options = [])
+    {
+        $this->name = $name;
+        $this->callable = $callable;
+        $this->options = array_merge([
+            'needs_environment' => false,
+            'needs_context' => false,
+            'is_variadic' => false,
+            'is_safe' => null,
+            'is_safe_callback' => null,
+            'node_class' => '\Twig\Node\Expression\FunctionExpression',
+            'deprecated' => false,
+            'alternative' => null,
+        ], $options);
+    }
+
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    public function getCallable()
+    {
+        return $this->callable;
+    }
+
+    public function getNodeClass()
+    {
+        return $this->options['node_class'];
+    }
+
+    public function setArguments($arguments)
+    {
+        $this->arguments = $arguments;
+    }
+
+    public function getArguments()
+    {
+        return $this->arguments;
+    }
+
+    public function needsEnvironment()
+    {
+        return $this->options['needs_environment'];
+    }
+
+    public function needsContext()
+    {
+        return $this->options['needs_context'];
+    }
+
+    public function getSafe(Node $functionArgs)
+    {
+        if (null !== $this->options['is_safe']) {
+            return $this->options['is_safe'];
+        }
+
+        if (null !== $this->options['is_safe_callback']) {
+            return \call_user_func($this->options['is_safe_callback'], $functionArgs);
+        }
+
+        return [];
+    }
+
+    public function isVariadic()
+    {
+        return $this->options['is_variadic'];
+    }
+
+    public function isDeprecated()
+    {
+        return (bool) $this->options['deprecated'];
+    }
+
+    public function getDeprecatedVersion()
+    {
+        return $this->options['deprecated'];
+    }
+
+    public function getAlternative()
+    {
+        return $this->options['alternative'];
+    }
+}
+
+class_alias('Twig\TwigFunction', 'Twig_SimpleFunction');
+
+// Ensure that the aliased name is loaded to keep BC for classes implementing the typehint with the old aliased name.
+class_exists('Twig\Node\Node');