[FIXES PR#1777] Make accessing pendingLaunches lock free

Update link to Groovy

Codehaus terminated all services - now Groovy's new home is groovy-lang.org.

- My objection to #1777 is that it is introducing more locking. The ultimate aim is to make
  node provisioning and queue maintenance completely lock free. Thus adding more locks than
  is strictly required is a bad plan.
- We cannot completely remove provisioningLock at this time as it is used to ensure that
  only one provisioning activity can take place for a given label at a time.
- This change ensures that the provisioningLock is only used by the NodeProvisioner for
  its internal thread guarantees and is thus no-longer used accidentally by any
  external threads

few chances there’s another implementation
but if one exists Function.isWindows would probably be wrong implementation

Avoid "EmptyStackException: null" in Items#getCanonicalName

Conflicts:
	core/src/main/resources/hudson/model/Messages.properties
	core/src/main/resources/hudson/model/Messages_de.properties
	core/src/main/resources/hudson/model/Messages_it.properties
	core/src/main/resources/hudson/model/Messages_ja.properties
	core/src/main/resources/hudson/model/Messages_zh_TW.properties
	core/src/main/resources/jenkins/model/Messages.properties
	core/src/main/resources/jenkins/model/Messages_da.properties
	core/src/main/resources/jenkins/model/Messages_de.properties
	core/src/main/resources/jenkins/model/Messages_es.properties
	core/src/main/resources/jenkins/model/Messages_fr.properties
	core/src/main/resources/jenkins/model/Messages_it.properties
	core/src/main/resources/jenkins/model/Messages_ja.properties
	core/src/main/resources/jenkins/model/Messages_nl.properties
	core/src/main/resources/jenkins/model/Messages_pt_BR.properties
	core/src/main/resources/jenkins/model/Messages_ru.properties
	core/src/main/resources/jenkins/model/Messages_tr.properties
	core/src/main/resources/jenkins/model/Messages_zh_CN.properties
	core/src/main/resources/jenkins/model/Messages_zh_TW.properties

Make it easier to determine Computer is Unix or Windows

[JENKINS-26147] New home for BUILD_NOW_TEXT

Deleting bogus class ExceptionInterruption

This reverts commit 68b383e0.

Reduce logging level

Null safety for hudson.model.Result

Use log4j-bridge of slf4j and dont ship log4j.

- 252e1296 doesn't work for all cases as there are code paths
  where a pending launch can be removed from the pending list and not have spent() called.
- There was no reason for iterating the list twice anyway, as all of this takes place with the locks held
- My notifying each one as we process, if there is an Error, we will not leave any stranded. The next run
  through, if there is one, will cover those instances.

... as a control case in the master branch to ensure the changes in the
config-ui-changes do not break its behaviour.