[Php72] Handle crash on trailing comma last on WhileEachToForeachRector

[samsonasik]

Given the following code:

final class TrailingCommaLast
{
    public function run()
    {
        while(list($code_name,) = each($poster_xd))
        {
            $poster_xd[$code_name] = preg_replace($orig_word, $replacement_word, $poster_xd[$code_name]);
        }
    }
}

It cause crash:

There was 1 error:

1) Rector\Tests\Php72\Rector\While_\WhileEachToForeachRector\WhileEachToForeachRectorTest::test with data set #3 ('/Users/samsonasik/www/rector-...hp.inc')
TypeError: PhpParser\Node\Stmt\Foreach_::__construct(): Argument #2 ($valueVar) must be of type PhpParser\Node\Expr, null given, called in /Users/samsonasik/www/rector-src/rules/Php72/Rector/While_/WhileEachToForeachRector.php on line 131

Ref https://getrector.org/demo/ec8b7f3a-918f-4bfe-bf70-28fa2a992916
Fixes rectorphp/rector#7654

The transformation should be

https://3v4l.org/mTeIL#v7.1.31 --> https://3v4l.org/UJH9S

[samsonasik]

Fixed 🎉 /cc @scottybcoder

[samsonasik]

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

[TomasVotruba]

Thank you 👏