fix about task execution in backups (eviction, write behind ops)
added delay for replication also
Fix the wan replication bug that propagates deletes back to other instances
Revert "Fix the wan replication bug that propagates deletes back to other instances"

This reverts commit 700524e287679429e9441308c49b4129d0f1a1b9.
Fix the wan replication bug that propagates deletes back to other wan instances
ClusterService scheduled tasks (heartbeater, split-brain handler etc) should run on their own executor. Otherwise when common scheduled executor stalls becuase of other tasks (mapstore etc), cluster tasks are delayed and that causes instabilities.
Test framework should set MemberImpl.lastRead time when a packet is sent.
Fixes #1551.
3.1.5-SNAPSHOT
Merge pull request #1546 from enesakar/postpone-backuptasks

fix about task execution in backups (eviction, write behind ops)
Merge pull request #1554 from mdogan/fix/3.2/cluster-heartbeater

ClusterService scheduled tasks (heartbeater, split-brain handler etc) should run on their own executor.
Also other usages of potential NPE caused by InteralPartition.getOwner have been checked
Merge pull request #1557 from pveentjer/fix/npe-mapservice-createlocalmapstats

Potential NPE caused by InteralPartition.getOwner
code cleanup
HzClusterUtil update
Merge pull request #1550 from jagliot/master

Fix the wan replication bug that propagates deletes back to other wan instance
Merge pull request #1558 from Danny-Hazelcast/HzClusterUtil

HzClusterUtil update