Cluster state bulk processing of a rapid deletion & creation of an index can cause usage of a wrong meta data #9489
Description
When a node falls behind in processing cluster states form the master, it processes the pending updates in bulk. If these bulk contains both a deletion and creation of the same index, the node may create new shard using the UUID of the old index. This will then cause the master to ignore the shard started notifications as the left overs of the previous index (since the index was just created, they shards are empty and they come in quickly). This can leave the shard as stuck in initializing.