MCP-584: Disable inventory check on quote load

- Add stock status check to prevent order placement with positive qty but with out of stock status when inventory check is disabled;

Author: adifucan

app/code/Magento/CatalogInventory/Model/StockManagement.php

@@ -119,7 +119,7 @@ public function registerProductsSale($items, $websiteId = null)
             ) {
                 $this->getResource()->commit();
                 throw new \Magento\Framework\Exception\LocalizedException(
-                    __('Not all of your products are available in the requested quantity.')
+                    __('Some of the products are out of stock.')
                 );
             }
             if ($this->canSubtractQty($stockItem)) {
@@ -137,7 +137,7 @@ public function registerProductsSale($items, $websiteId = null)
         }
         $this->qtyCounter->correctItemsQty($registeredItems, $websiteId, '-');
         $this->getResource()->commit();
-        
+
         return $fullSaveItems;
     }
 

app/code/Magento/CatalogInventory/Model/StockStateProvider.php

@@ -249,6 +249,9 @@ public function checkQty(StockItemInterface $stockItem, $qty)
         if (!$stockItem->getManageStock()) {
             return true;
         }
+        if (!$stockItem->getIsInStock()) {
+            return false;
+        }
         if ($stockItem->getQty() - $stockItem->getMinQty() - $qty < 0) {
             switch ($stockItem->getBackorders()) {
                 case \Magento\CatalogInventory\Model\Stock::BACKORDERS_YES_NONOTIFY: