HTML output directory sites/simpletest/browser_output is not a writable directory.

PHPUnit 11.5.56 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.21
Configuration: /var/www/html/web/core/phpunit.xml.dist

................................................................. 65 / 83 ( 78%)
..................                                                83 / 83 (100%)

Time: 00:00.285, Memory: 16.00 MB

OK, but there were issues!
Tests: 83, Assertions: 329, PHPUnit Deprecations: 59.
