SERVER-29213 will break the powercycle_replication tests ability to query for the canary document after a crash. As such, that patch is temporarily disabling them.
SERVER-29213, bringing a node up in standalone may result in stale data relative to what the node has accepted. The node has not lost the data, but simply, replication recovery needs to be done for the data to be queryable.
The powercycle tests bring a node back up to check for the canary document in standalone mode and the node is brought up on a different port than is used when running as a replica set member.
SERVER-34070 will make it easier to make the required changes to re-enable the powercycle_replication* tests. What's problematic is that running replication recovery requires starting the node up with the --replSet option. However, a node running with --replSet on a different port than in the replset config will not come up as a PRIMARY nor SECONDARY and thus not service reads.