Stop the raft node to not cause test to flap.

Test TestNoRaceJetStreamClusterCorruptWAL() would start to flap
because of the snapshot on cluster shutdown. Disable the snapshot
on exit for this test by stopping the raft node before shutdown.

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>

server/norace_test.go

@@ -3562,6 +3562,8 @@ func TestNoRaceJetStreamClusterCorruptWAL(t *testing.T) {
 	}
 	// Grab underlying raft node and the WAL (filestore) and we will attempt to "corrupt" it.
 	node := o.raftNode().(*raft)
+	// We are doing a stop here to prevent the internal consumer snapshot from happening on exit
+	node.Stop()
 	fs := node.wal.(*fileStore)
 	fcfg, cfg := fs.fcfg, fs.cfg.StreamConfig
 	// Stop all the servers.