Simplify code base based on improved error handling in PHP 8

[arogachev]

For example - https://php.watch/versions/8.0/internal-function-exceptions.

[vjik]

Where exactly?

[arogachev]

@vjik

• https://github.com/yiisoft/proxy/pull/21/files#r884785022
• https://github.com/yiisoft/files/blob/master/src/FileHelper.php#L45

[vjik]

Actual link to example in yiisoft/proxy: yiisoft/proxy#21 (comment)