[php-src] Issue #7873: Adding __toString method to class defined below instantiation causes class to not be detected

Issue: https://github.com/php/php-src/issues/7873 Author: pocallaghan ### Description This is probably considered non-standard usage, but I stumbled over it by accident. The following code: ```php <?php $foo = new Test; var_dump($foo); class Test { public function __toString() { return ''; } } ``` Resulted in this output: ``` PHP Fatal error: Uncaught Error: Class "Test" not found in /private/tmp/foo.php:3 Stack trace: #0 {main} thrown in /private/tmp/foo.php on line 3 Fatal error: Uncaught Error: Class "Test" not found in /private/tmp/foo.php:3 Stack trace: #0 {main} thrown in /private/tmp/foo.php on line 3 ``` But I expected this output instead: ``` object(Test)#1 (0) { } ``` If you remove the __toString method from the class, the code functions as expected. ### PHP Version 8.1.1 ### Operating System _No response_