[DeadCode] Add ReplaceBlockToItsStmtsRector

[samsonasik]

This PR inspired by @tacman use case at:

• "System error: "Scope not available  rector#8956

that handled at PR:

• [CodeQuality] Handle crash inside Block { } statement with unreachable statement on OptionalParametersAfterRequiredRector #6640

the block statement should never used imo, as it always executed, direct replace with its stmts instead.

{
    echo "statement 1";
    echo PHP_EOL;
    echo "statement 2";
}

see https://3v4l.org/ZUfEV

[samsonasik]

All checks have passed 🎉 @TomasVotruba it is ready for review.

[TomasVotruba]

Looks good 👍

[samsonasik]

Thank you @TomasVotruba for the review, let's merge 👍