Since PHP 8.0 robo outputs silenced errors

[MartinMystikJonas]

Steps to reproduce

Use robo to run code that uses erro silencing operator (@) to silence expected errors

Expected behavior

Silenced errors should not be shown

Actual behavior

Robo outputs silenced error because handleError returns false and error_get_last() inside shutdown handler then return silenced error.

System Configuration

This happens since PHP 8.0 because error_reporting() in error handler for silenced errors does not return 0 as before.

Prior to PHP 8.0.0, the [error_reporting()](https://www.php.net/manual/en/function.error-reporting.php) called inside the custom error handler always returned 0 if the error was suppressed by the @ operator. As of PHP 8.0.0, it returns the value E_ERROR | E_CORE_ERROR | E_COMPILE_ERROR | E_USER_ERROR | E_RECOVERABLE_ERROR | E_PARSE.

See https://www.php.net/manual/en/language.operators.errorcontrol.php