[TASK] Resolve fatal errors in unit tests under PHP 8.1

PHP 8.1 now includes types on built in class's properties, which means
redeclaring them without types breaks. Let's not do that.

This patch resolves all hard-fatals in unit tests, but not all errors.

Resolves: #95155
Releases: master
Change-Id: Ied1b8c3c9f35692f0fe2a793972f06cb3ef79d7f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70972


Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>

typo3/sysext/core/Classes/IO/CsvStreamFilter.php

@@ -27,13 +27,6 @@ class CsvStreamFilter extends \php_user_filter
 {
     protected const NAME = 'csv.typo3';
 
-    /**
-     * @var array contains 'sequence' key for stream filter
-     * @private
-     * @internal
-     */
-    public $params = [];
-
     /**
      * Implicitly handles stream filter when writing CSV data - example:
      *