[DeadCode] Improve RemoveUnreachableStatementRector performance by re…

…turn after array_splice early (#2193)

* [DeadCode] Improve RemoveUnreachableStatementRector by flag removed early on loop

* fill, return early

* use array_splice

rules/DeadCode/Rector/Stmt/RemoveUnreachableStatementRector.php

@@ -120,7 +120,6 @@ public function refactor(Node $node): ?Node
      */
     private function processCleanUpUnreachabelStmts(array $stmts): array
     {
-        $originalStmts = $stmts;
         foreach ($stmts as $key => $stmt) {
             if (! isset($stmts[$key - 1])) {
                 continue;
@@ -133,17 +132,12 @@ private function processCleanUpUnreachabelStmts(array $stmts): array
             $previousStmt = $stmts[$key - 1];
 
             if ($this->shouldRemove($previousStmt, $stmt)) {
-                unset($stmts[$key]);
-                break;
+                array_splice($stmts, $key);
+                return $stmts;
             }
         }
 
-        if ($originalStmts === $stmts) {
-            return $originalStmts;
-        }
-
-        $stmts = array_values($stmts);
-        return $this->processCleanUpUnreachabelStmts($stmts);
+        return $stmts;
     }
 
     private function shouldRemove(Stmt $previousStmt, Stmt $currentStmt): bool