[php-src] Issue #9845: `empty("0")` returns `true` when it should return `false`

Issue: https://github.com/php/php-src/issues/9845 Author: NiklasBr ### Description The following code: ```php <?php // A string of length 1 with an ASCII character such as zero var_dump(empty('0')); // A string of length 1 with an ASCII character such as a letter var_dump(empty('A')); ``` Resulted in this output: ``` bool(true) bool(false) ``` But I expected this output instead: ``` bool(false) bool(false) ``` ## I expected this because The documentation states: > A variable is considered empty if it does not exist or if its value equals false. But "0" === false is not true. ### PHP Version 8.1.11 ### Operating System _No response_