Today a common reason for a `ShardLockObtainFailedException` is when a
shard is removed from a node and then assigned straight back to it again
before the node has had a chance to shut the previous shard instance
down. For instance, this can happen if a node briefly leaves the cluster
holding a primary with no in-sync replicas.
The message in this case is typically as follows:
obtaining shard lock timed out after 5000ms, previous lock details: [shard creation] trying to lock for [shard creation]
This is pretty hard to interpret, and doesn't raise the important
question: "why didn't the shard shut down sooner?"
With this change we reword the message a bit, report the age of the
shard lock, and adjust the details to report that the lock is held by a
closing shard:
obtaining shard lock for [starting shard] timed out after [5000ms], lock already held for [closing shard] with age [12345ms]
Relates #38807
389f7779e7