[DeadCode] Skip RemoveDeadIfBlockRector on empty if with elseif and trailing else

An empty if body followed by elseif and else was merged into
"if (!cond && elseifCond) {...} else {...}". When the original if
condition was true, the negated condition made the else branch run,
which the empty if body never did. Keep such code unchanged.

Fixes rectorphp/rector#9884

Claude-Session: https://claude.ai/code/session_01MszFhfN8nK7KR3mBjda8P2

Author: TomasVotruba

…re/empty_if_with_elseif_and_else.php.inc …ip_empty_if_with_elseif_and_else.php.incrules-tests/DeadCode/Rector/If_/RemoveDeadIfBlockRector/Fixture/empty_if_with_elseif_and_else.php.inc renamed to rules-tests/DeadCode/Rector/If_/RemoveDeadIfBlockRector/Fixture/skip_empty_if_with_elseif_and_else.php.inc rules-tests/DeadCode/Rector/If_/RemoveDeadIfBlockRector/Fixture/empty_if_with_elseif_and_else.php.inc renamed to rules-tests/DeadCode/Rector/If_/RemoveDeadIfBlockRector/Fixture/skip_empty_if_with_elseif_and_else.php.inc

@@ -18,23 +18,3 @@ class EmptyIfWithElseIfAndElse
 }
 
 ?>
------
-<?php
-
-namespace Rector\Tests\DeadCode\Rector\If_\RemoveDeadIfBlockRector\Fixture;
-
-class EmptyIfWithElseIfAndElse
-{
-    public function calculatePrice($qty, $cond, $price1, $price2)
-    {
-        if ($qty >= 1 && !$cond) {
-            $total = $qty * $price1;
-        } else {
-            $total = $qty * $price2;
-        }
-
-        return $total;
-    }
-}
-
-?>

rules/DeadCode/Rector/If_/RemoveDeadIfBlockRector.php

@@ -131,6 +131,12 @@ public function refactor(Node $node): int|null|If_
         // When the if body is blank but it has an elseif,
         // merge the negated if condition with the elseif condition
         if ($node->elseifs !== []) {
+            // A trailing else would run when the negated if condition is true,
+            // which the original empty if body never did, so keep the code as is.
+            if ($node->else instanceof Else_) {
+                return null;
+            }
+
             $firstElseIf = $node->elseifs[0];
             $cond = new BooleanAnd(
                 $this->conditionInverter->createInvertedCondition($node->cond),