gms/gossiper: Replicate STATUS change from mark_as_shutdown() to other shards
gms/gossiper: Replicate STATUS change from mark_as_shutdown() to other shards

Lack of this may result in non-zero shards on some nodes still seeing
STATUS as NORMAL for a node which shut down, in some cases.

mark_as_shutdown() is invoked in reaction to an RPC call initiated by
the node which is shutting down. Another way a node can learn about
other node shutting down is via gossiping with a node which knows
this. In that case, the states will be replicated to non-zero
shards. The node which learnt via mark_as_shutdown() may also
eventually propagate this to non-zero shards, e.g. when it gossips
about it with other nodes, and its local version number at the time of
mark_as_shudown() was smaller than the one used to set the STATE by
the shutting down node.

scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla