Incorrect behavior of RemoveUnusedPrivateMethodRector

[tugmaks]

Fixes rectorphp/rector#6507

[samsonasik]

Please add 1 more test case for case insensitive:

final class SkipArrayCallablesThisCaseInSensitiveMethodName
 {
     public function run()
     {
         $array  = [3, 2, 1];

         usort($array, [$this, 'sortCaseInSensitiveMethodName']);

         return $array;
     }

     private function sortCaseInSensitiveMETHODName($a, $b)
     {
         return $a <=> $b;
     }
 }

[tugmaks]

@samsonasik https://github.com/rectorphp/rector-src/blob/main/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodRector/Fixture/skip_array_callables_this.php.inc

[samsonasik]

We need insencitive case one, which I tried your patch locally with insensitive "sortCaseInSensitiveMETHODName" and got failure.

[tugmaks]

@samsonasik done

[TomasVotruba]

Thank you