[php-src] Issue #7821: Can't use inherited constant value via 'self'

Issue: https://github.com/php/php-src/issues/7821 Author: wbars ### Description The following code: ```php <?php interface I { public const DEFAULT_VALUE = 'gambrinus'; } enum Beer: string implements I { // case GAMBRINUS = I::DEFAULT_VALUE; case GAMBRINUS = self::DEFAULT_VALUE; } var_dump(Beer::GAMBRINUS); ``` Resulted in this output: ``` Fatal error: Enum case value must be compile-time evaluatable in /in/Oqm7f on line 9 ``` But I expected this output instead: No errors, because commented case GAMBRINUS = I::DEFAULT_VALUE produces no error ### PHP Version 8.1.1 ### Operating System _No response_