Issue magento/magento2#18094: Should getQty() return int/float or string

 - remove typecasting from the setter

Author: Oleksii Korshenko

app/code/Magento/Catalog/Model/Product.php

@@ -972,7 +972,7 @@ public function afterSave()
     public function setQty($qty)
     {
         if ($this->getData('qty') != $qty) {
-            $this->setData('qty', (float)$qty);
+            $this->setData('qty', $qty);
             $this->reloadPriceInfo();
         }
         return $this;