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/Expression/ArrayExpression.php

@@ -0,0 +1,88 @@
+<?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\Expression;
+
+use Twig\Compiler;
+
+class ArrayExpression extends AbstractExpression
+{
+    protected $index;
+
+    public function __construct(array $elements, $lineno)
+    {
+        parent::__construct($elements, [], $lineno);
+
+        $this->index = -1;
+        foreach ($this->getKeyValuePairs() as $pair) {
+            if ($pair['key'] instanceof ConstantExpression && ctype_digit((string) $pair['key']->getAttribute('value')) && $pair['key']->getAttribute('value') > $this->index) {
+                $this->index = $pair['key']->getAttribute('value');
+            }
+        }
+    }
+
+    public function getKeyValuePairs()
+    {
+        $pairs = [];
+
+        foreach (array_chunk($this->nodes, 2) as $pair) {
+            $pairs[] = [
+                'key' => $pair[0],
+                'value' => $pair[1],
+            ];
+        }
+
+        return $pairs;
+    }
+
+    public function hasElement(AbstractExpression $key)
+    {
+        foreach ($this->getKeyValuePairs() as $pair) {
+            // we compare the string representation of the keys
+            // to avoid comparing the line numbers which are not relevant here.
+            if ((string) $key === (string) $pair['key']) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    public function addElement(AbstractExpression $value, AbstractExpression $key = null)
+    {
+        if (null === $key) {
+            $key = new ConstantExpression(++$this->index, $value->getTemplateLine());
+        }
+
+        array_push($this->nodes, $key, $value);
+    }
+
+    public function compile(Compiler $compiler)
+    {
+        $compiler->raw('[');
+        $first = true;
+        foreach ($this->getKeyValuePairs() as $pair) {
+            if (!$first) {
+                $compiler->raw(', ');
+            }
+            $first = false;
+
+            $compiler
+                ->subcompile($pair['key'])
+                ->raw(' => ')
+                ->subcompile($pair['value'])
+            ;
+        }
+        $compiler->raw(']');
+    }
+}
+
+class_alias('Twig\Node\Expression\ArrayExpression', 'Twig_Node_Expression_Array');