[FAB-15980] IT: stop the leader peer
[FAB-15980] IT: stop the leader peer

This CR is to execute IT: stop the leader peer,
send TXs, and restart it to confirm that it
steps dwon and catches up as a nonleader

Signed-off-by: Dongming <8a44bf95374aee2f65c5ee249f73073c9eb07cf5@ibm.com>
Change-Id: I975b1bf9623191b0bc434067f6ae5fd9fc3f08c5

manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric-sidedb,jimthematrix/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric,manish-sethi/fabric-sidedb,hyperledger/fabric,manish-sethi/fabric,binhn/fabric,muralisrini/fabric,stemlending/fabric,binhn/fabric,binhn/fabric,jimthematrix/fabric,hyperledger/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,stemlending/fabric