MAGETWO-67240: Duplicate and broken products appear after import

Author: andimov

app/code/Magento/CatalogImportExport/Model/Import/Product.php

@@ -1608,7 +1608,7 @@ protected function _saveProducts()
                     ];
                 } else {
                     if (!$productLimit || $productsQty < $productLimit) {
-                        $entityRowsIn[$rowSku] = [
+                        $entityRowsIn[strtolower($rowSku)] = [
                             'attribute_set_id' => $this->skuProcessor->getNewSku($rowSku)['attr_set_id'],
                             'type_id' => $this->skuProcessor->getNewSku($rowSku)['type_id'],
                             'sku' => $rowSku,