fix a race condition in ClusterReadView #24710 (#26922)

* remove lazy initialization for _cachedSelf
* don't update _state and friends after close()

akka-cluster/src/multi-jvm/scala/akka/cluster/MinMembersBeforeUpSpec.scala

@@ -118,7 +118,6 @@ abstract class MinMembersBeforeUpBase(multiNodeConfig: MultiNodeConfig)
     runOn(first) {
       cluster.join(myself)
       awaitAssert {
-        clusterView.refreshCurrentState()
         clusterView.status should ===(Joining)
       }
     }
@@ -132,7 +131,6 @@ abstract class MinMembersBeforeUpBase(multiNodeConfig: MultiNodeConfig)
     runOn(first, second) {
       val expectedAddresses = Set(first, second).map(address)
       awaitAssert {
-        clusterView.refreshCurrentState()
         clusterView.members.map(_.address) should ===(expectedAddresses)
       }
       clusterView.members.unsorted.map(_.status) should ===(Set(Joining))

akka-cluster/src/multi-jvm/scala/akka/cluster/MultiNodeClusterSpec.scala

@@ -251,7 +251,6 @@ trait MultiNodeClusterSpec extends Suite with STMultiNodeSpec with WatchedByCoro
     cluster.join(joinNode)
     awaitCond(
       {
-        clusterView.refreshCurrentState()
         if (memberInState(joinNode, List(MemberStatus.Up)) &&
             memberInState(myself, List(MemberStatus.Joining, MemberStatus.Up)))
           true

akka-cluster/src/multi-jvm/scala/akka/cluster/TransitionSpec.scala

@@ -65,12 +65,10 @@ abstract class TransitionSpec
   }
 
   def awaitMembers(addresses: Address*): Unit = awaitAssert {
-    clusterView.refreshCurrentState()
     memberAddresses should ===(addresses.toSet)
   }
 
   def awaitMemberStatus(address: Address, status: MemberStatus): Unit = awaitAssert {
-    clusterView.refreshCurrentState()
     memberStatus(address) should ===(status)
   }