[php-src] Issue #14867: addslashes() fails to escape the NUL byte correctly.

Issue: https://github.com/php/php-src/issues/14867 Author: Wiimm ### Description The following code: ``echo addslashes("\00040");'`` Resulted in this output: ``\040`` (same as "!"). But I expected this output instead: ``\00040`` (NUL + "40") The issue is, that the NUL byte is escaped to ``\0``. But if the NUL byte is followed by valid octal digits, up of 2 of them will be interpreted as part of the escape. **Solution:** Always escape the NUL byte to ``\000``. ### PHP Version PHP 7.2.5 .. 8.3.7 ### Operating System OpenSUSE, Debian