Fix some PHP 8.2 deprecations (#319)

* Define HTMLPurifier_Lexer::$_entity_parser property

This fixes a PHP 8.2 deprecation.

* Define HTMLPurifier_URIFilterHarness::$filter property

This fixes a PHP 8.2 deprecation.

* Define HTMLPurifier_AttrTransform_NameSync::$idDef property

This fixes a PHP 8.2 deprecation.

* Define HTMLPurifier_AttrTransform_NameSyncTest::$accumulator property

This fixes a PHP 8.2 deprecation.

* Define HTMLPurifier_AttrValidator_ErrorsTest::$language property

This fixes a PHP 8.2 deprecation.

* Define HTMLPurifier_ChildDef_List::$whitespace property

This fixes a PHP 8.2 deprecation.

* Do not modify incoming tokens in RemoveSpansWithoutAttributes

Previously the undefined property `->markForDeletion` was added to the incoming
tokens. This causes a deprecation in PHP 8.2. Fix this by storing to-be-deleted
tokens inside SplObjectStorage. In PHP 8 a WeakMap would be preferable, as that
prevents leaks if `handleEnd` is never called for the token.

tests/HTMLPurifier/AttrTransform/NameSyncTest.php

@@ -3,6 +3,11 @@
 class HTMLPurifier_AttrTransform_NameSyncTest extends HTMLPurifier_AttrTransformHarness
 {
 
+    /**
+     * @type HTMLPurifier_IDAccumulator
+     */
+    public $accumulator;
+
     public function setUp()
     {
         parent::setUp();

tests/HTMLPurifier/AttrValidator_ErrorsTest.php

@@ -3,6 +3,11 @@
 class HTMLPurifier_AttrValidator_ErrorsTest extends HTMLPurifier_ErrorsHarness
 {
 
+    /**
+     * @type HTMLPurifier_Language
+     */
+    public $language;
+
     public function setup()
     {
         parent::setup();

tests/HTMLPurifier/URIFilterHarness.php

@@ -3,6 +3,11 @@
 class HTMLPurifier_URIFilterHarness extends HTMLPurifier_URIHarness
 {
 
+    /**
+     * @type HTMLPurifier_URIFilter
+     */
+    public $filter;
+
     protected function assertFiltering($uri, $expect_uri = true)
     {
         $this->prepareURI($uri, $expect_uri);