[php-src] PR #23903: Fix GH-23896: Assertion failure in zend_call_function() after a throwing deprecation

Pull Request: https://github.com/php/php-src/pull/23903 Author: lazerg Since GH-21699, zend_is_callable_check_class() returns false without setting error when the error handler throws on the self/parent/static deprecation. zend_call_function() asserted that a failed callable check always comes with an error message, so calling such a string callback through call_user_function() (here unserialize_callback_func=parent::...) aborts on debug builds. When the check fails with no error, the exception from the handler is already pending, so zend_call_function() now returns early without throwing a second one, the same way it does when it is entered with an exception. Fixes GH-23896