B2B-2033: [AWS S3] [Integration Tests]: Investigate Test Failures in ScheduledImportExport module

Author: oshmyheliuk

app/code/Magento/ImportExport/Model/Import.php

@@ -638,10 +638,11 @@ public function uploadFileAndGetSource()
      */
     protected function _removeBom($sourceFile)
     {
-        $string = $this->_varDirectory->readFile($this->_varDirectory->getRelativePath($sourceFile));
+        $driver = $this->_varDirectory->getDriver();
+        $string = $driver->fileGetContents($this->_varDirectory->getAbsolutePath($sourceFile));
         if ($string !== false && substr($string, 0, 3) == pack("CCC", 0xef, 0xbb, 0xbf)) {
             $string = substr($string, 3);
-            $this->_varDirectory->writeFile($this->_varDirectory->getRelativePath($sourceFile), $string);
+            $driver->filePutContents($this->_varDirectory->getAbsolutePath($sourceFile), $string);
         }
         return $this;
     }