Improve code quality

Author: kandy

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

@@ -214,7 +214,7 @@ private function getAttributeId()
      */
     private function retrieveAffectedIds(array $skus)
     {
-        $affectedIds = [];
+        $affectedIds = [[]];
 
         foreach ($this->productIdLocator->retrieveProductIdsBySkus($skus) as $productIds) {
             $affectedIds[] = array_keys($productIds);

dev/tests/integration/framework/Magento/TestFramework/Helper/Memory.php

@@ -53,7 +53,6 @@ public function getRealMemoryUsage()
             // fall back to the Unix command line
             $result = $this->_getUnixProcessMemoryUsage($pid);
         } catch (\Magento\Framework\Exception\LocalizedException $e) {
-            echo  $e;
             // try to use the Windows command line
             // some ports of Unix commands on Windows, such as MinGW, have limited capabilities and cannot be used
             $result = $this->_getWinProcessMemoryUsage($pid);