Fix (bug #1862): Do not clear entity manager for doctrine orm populator

src/Faker/ORM/Doctrine/Populator.php

@@ -98,11 +98,9 @@ public function execute($entityManager = null)
                 );
                 if (count($insertedEntities) % $this->batchSize === 0) {
                     $entityManager->flush();
-                    $entityManager->clear($class);
                 }
             }
             $entityManager->flush();
-            $entityManager->clear($class);
         }
 
         return $insertedEntities;