[php-src] Issue #7976: is_readable() not working on files inside phar

Issue: https://github.com/php/php-src/issues/7976 Author: petitj ### Description Using the following code to create a basic phar file: ```php $stub = <<<STUB <?php Phar::interceptFileFuncs(); set_include_path("phar://archive.phar" . PATH_SEPARATOR . get_include_path()); include "index.php"; __HALT_COMPILER(); STUB; $phar = new Phar('archive.phar'); $phar->addFromString('index.php', '<?php echo "Hello World" . PHP_EOL;'); $phar->setStub($stub); ``` Then executing the following code: ```php <?php var_dump(is_readable('/path/to/archive.phar/index.php')); ``` Resulted in this output: ``` bool(false) ``` But I expected this output instead: ``` bool(true) ``` This also happens for calls made from code executed inside the phar. ### PHP Version PHP 8.0.12 ### Operating System Ubuntu 20.04