Fixes #8009

Flush full page cache for all products that have been reindexed. Not only the child products, but also parent products. This is already the case in 2.2-develop.

Author: Anton Evers

app/code/Magento/CatalogInventory/Model/Indexer/Stock/AbstractAction.php

@@ -248,7 +248,7 @@ protected function _reindexRows($productIds = [])
             }
         }
 
-        $this->cacheContext->registerEntities(Product::CACHE_TAG, $productIds);
+        $this->cacheContext->registerEntities(Product::CACHE_TAG, $processIds);
         $this->eventManager->dispatch('clean_cache_by_tags', ['object' => $this->cacheContext]);
 
         return $this;