* calcualte global-checkpoint from pd written by tikv Signed-off-by: joccau <zak.zhao@pingcap.com> * log-status shows storage checkpoint Signed-off-by: joccau <zak.zhao@pingcap.com> * add test case Signed-off-by: joccau <zak.zhao@pingcap.com> * show red status if the checkpoint gap > 10min Signed-off-by: joccau <zak.zhao@pingcap.com> Co-authored-by: 3pointer <luancheng@pingcap.com> Co-authored-by: Ti Chi Robot <ti-community-prow-bot@tidb.io>