(cherry picked from commit d3ebb8a5)

This reverts commit 48ef1542, reversing
changes made to dc4a9b1f.

[FIXED JENKINS-24696] Cannot assume that Jenkins.getInstance() != null when we are running a boot failure script.
(cherry picked from commit 42de07bb)

(cherry picked from commit 09722a98)

[FIXED JENKINS-24696] Cannot assume that Jenkins.getInstance() != null when we are running a boot failure script.
(cherry picked from commit 42de07bb)

(cherry picked from commit 09722a98)

(cherry picked from commit d8a13ac0)

(cherry picked from commit 758c0ced)

[JENKINS-31932] avoid synchronization for Jenkinsget/setJDKs
(cherry picked from commit 0a5b0368)

[FIXED JENKINS-31219] A CloudProvisioningListener can prevent provisioning of all clouds instead of just the targeted cloud

(cherry picked from commit cc932c49)

This change adds code to check that the user isn't attempting to rename
an existing node with the name of another existing node.  Previous to
this change, such rename operations would succeed and would corrupt node
configuration data.

(cherry picked from commit 16d6429c)

(cherry picked from commit 8f012d63)

create a specific implementation for Idle Offline Cause

Specify --webroot to the Windows service wrapper

Docker images and other automation use cases often want to make Jenkins
use specific port. Today they do this via init.groovy.d with a
problematic sleep timeout, so allow them to control this value via
system property.

[FIX JENKINS-11016] Add button that allows retrying core update

[FIXED JENKINS-31219] A CloudProvisioningListener can prevent provisi…

[FIXED JENKINS-31954] Stack overflow reconfiguring some settings where Descriptor.newInstance is gratuitously overridden.