Show stack trace only if system property is set.

They really belong in Stapler anyway, but they're easier here.

And clean up a few tests.

Show it to everybody if the system property is set.

Check isCommitted().
Guard against circular causes when checking for AccessDeniedException.

Merge pull request #4484 from contextshuffling/hudson.util.ArgumentListBuilderTest#assertKeyValuePairsWithMask

[JENKINS-61024] Use LinkedHashMap for deterministic iterations

Increase timeout on test to stop flaking

* Upgrade to 4.2 version of Remoting.

* Upgrade to slave-installer 1.7.

[JENKINS-60867] Prevent creation of duplicated SetupWizard singleton instances on Jenkins startup (#4456)

* [JENKINS-60867] Blank page after SetupWizard: root cause

* Correct a test that was a bit too greedy

Release Drafter: Do not use `regression-fix` label for the changelog, use the global template (#4481)

* Release Drafter: Do not use `regression-fix` label for the changelog, clarify the category headers

* Release Drafter: use categories from the org-wide settings

Enforce singleton pattern in CaseInsensitiveComparator

* Export if plugin update is compatible

* Remove the erorr usage of Exported annoation

* Remove unclear export annotation

* Remove multicast discovery services.

* Refine clean up with DNSMultiCast.

Doesn't need to be referenced in the other pom any more.
We need to keep the class and the property around for a while.
Jenkins Test Harness sets the property. Until we can get all
versions aligned so it isn't needed, it's best to keep the property
doing nothing.

* Deprecate remaining class fragment.

* Remove unneeded dependency.

* Improve code comments for external usages.
Co-Authored-By: NJesse Glick <jglick@cloudbees.com>

* Remove multicast discovery services.

* Refine clean up with DNSMultiCast.

Doesn't need to be referenced in the other pom any more.
We need to keep the class and the property around for a while.
Jenkins Test Harness sets the property. Until we can get all
versions aligned so it isn't needed, it's best to keep the property
doing nothing.

* Deprecate remaining class fragment.

* Remove unneeded dependency.

* Add log warning messages.

* Don't need to implement the interface anymore.

* Fix initializer.

Change capitalization for logger.

* Add URLs to log messages.
Co-Authored-By: NDaniel Beck <1831569+daniel-beck@users.noreply.github.com>
Co-authored-by: NJesse Glick <jglick@cloudbees.com>
Co-authored-by: NDaniel Beck <1831569+daniel-beck@users.noreply.github.com>

* add configuration-as-code as suggested

[JENKINS-21837] Do not record user creating an agent

[JENKINS-54496] - Don't log node-monitoring errors from deleted nodes