Update AbstractNodeQueue.java

Avoid spinning on head when a peek/poll observes a null next but the queue is not empty.
Update AbstractNodeQueue.java

language language....
=con #15613 Rename one of the DistributedPubSubMediatorSpec classes
+con #13737 Interceptors chain for Actors' bahavior.

* Add new pattern to akka-contrib.
* Mixin ReceivePipeline trait into Actors that have to be intercepted.
Merge pull request #15629 from akka/wip-15613-rename-DistributedPubSubMediatorSpec-patriknw

=con #15613 Rename one of the DistributedPubSubMediatorSpec classes
=tes #15167 Harden TestTimeSpec
Merge pull request #1869 from ktonga/wip-3737-interceptors-chain-for-receive-ktonga

#3737 Interceptors chain for receive
+act - #15501 - Adding support for a Non-blocking, bounded, MPMC mailbox called 'NonBlockingBoundedMailbox'
Fix isEmpty() and count()

isEmpty() need not rely on peek(which is intended for consumer use) and instead compare head to tail.
count() should stop counting at max int to avoid wrap.
Fixe documentation to state consumer only access is allowed to poll/peek/peekNode/pollNode
Doc stars err
Forgotten bracket
=act Fix typo in ActorRef Java example
+act,slf #11715 Add configurable LoggingFilter

* The filter is used by the LoggingAdapter before publishing
  to the event bus
* Slf4jLoggingFilter uses backend log level configuration
  (e.g. logback.xml)
Merge pull request #15637 from akka/wip-15167-TestTimeSpec-patriknw

=tes #15167 Harden TestTimeSpec
Merge pull request #15413 from akka/wip-11715-logging-filter-patriknw

+act,slf #11715 Add configurable LoggingFilter
=per #15590 Increase efforts to in-order on start of ALOD

AtLeastOnceDelivery can delivery out-of-order, and that's OK.
Although, in the case of message replay followed by taking user land
commands which may trigger `deliver` calls, it is nicer to at least once
try to send the replayed but not confirmed deliveries *first*, before
sending the completely new deliveries.

This change acomplishes this by triggering redelivery explicitly when
recovery has finished, and setting the timestamps on these messages a
bit in the past, so they hit their redelivery deadline right away during
this recovery induced redelivery.

Resolves #15590
Merge pull request #15645 from jonas/actorref-java-example-typo

=act Fix typo in ActorRef Java example
Merge pull request #15653 from akka/port-impr-efforts-to-in-order-during-replay-ALOD-ktoso

=per #15590 Increase efforts to in-order on start of ALOD (for Validation)
=tes Increase coroner timeout for some tests