Issue 1:
check_after_deref cur_backup.c:295
https://coverity.corp.mongodb.com/reports.htm#v15167/p10049/fileInstanceId=28531380&defectInstanceId=19249806&mergedDefectId=113990
WT-5206 Return the correct checkpoint-modified list of blocks
WT-5327 Backup cursor API can fail to restore WT_SESSION name information