[TEST] Added test that verifies that no shard relocations happen during / after a master re-election.
[TEST] Use assertBusy instead of awaitBusy
[Discovery] Master fault detection and nodes fault detection should take cluster name into account.

Both master fault detection and nodes fault detection request should also send the cluster name, so that on the receiving side the handling of these requests can be failed with an error. This error can be caught on the sending side and for master fault detection the node can fail the master locally and for nodes fault detection the node can be failed.

Note this validation will most likely never fail in a production cluster, but in during automated tests where cluster / nodes are created and destroyed very frequently.
Improve releases