Otherwise you get:
java.lang.AssertionError: class org.jvnet.hudson.test.ExtractResourceWithChangesSCM is missing its descriptor
	at jenkins.model.Jenkins.getDescriptorOrDie(Jenkins.java:1166)
	at hudson.scm.SCM.getDescriptor(SCM.java:654)
	at hudson.scm.AutoBrowserHolder.get(AutoBrowserHolder.java:54)
	at hudson.scm.SCM.getEffectiveBrowser(SCM.java:136)
	at hudson.scm.ChangeLogSet.browserFromBuild(ChangeLogSet.java:82)
	at hudson.scm.ChangeLogSet.<init>(ChangeLogSet.java:76)
	at org.jvnet.hudson.test.ExtractChangeLogSet.<init>(ExtractChangeLogSet.java:41)
	at org.jvnet.hudson.test.ExtractChangeLogParser.parse(ExtractChangeLogParser.java:80)
	at org.jvnet.hudson.test.ExtractChangeLogParser.parse(ExtractChangeLogParser.java:52)
	at org.jvnet.hudson.test.ExtractChangeLogParser.parse(ExtractChangeLogParser.java:46)
	at hudson.model.AbstractBuild.calcChangeSet(AbstractBuild.java:894)
	at hudson.model.AbstractBuild.access$600(AbstractBuild.java:104)
	at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:634)
	at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:86)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:528)
	at hudson.model.Run.execute(Run.java:1745)
	at …

PluginAutomaticTestBuilder improvements

[FIXED JENKINS-28690] Deadlock in hudson.model.Executor

NPE fix for AbstractProject polling when node is not available

[FIXED JENKINS-28041] - Allow delete-* CLI commands to operate on multiple arguments

- Rather fun one here. The Lock code relies on assuming that Thread.interrupted() is clear on entry
- If it then sees Thread.interrupted() set, it will interrupt the current thread in order to set the
  flag again.
- Executor is a thread that does funky things with an overridden interrupt method
- Executor.abortResult() is used to track a build be interrupted or aborted in some other way
- As a result the abortResult can cause a deadlockif there is a genuine interruption
- This fix clears the interrupt flag in abortResult() and uses the write lock in order to ensure:
    - The same lock as used in interrupt() is helf
    - The interrupt flag is clear
- Clearing the interrupt flag should be safe as the only time it is called is immediately after
  an interruption and the resulting exception is caught and rethrown/logged anyway

[FIXED JENKINS-28654] - Check null nodes condition in AbstractProject constructor

[FIX JENKINS-27739] Clear cached env vars when node goes online

View getView(String name): checkPermission() -> hasPermission() and return NULL if the user doesn't have a READ permission

[FIXED JENKINS-28704] Regression for build-history link not opening console

Null safety for removeExecutor

Sometimes observed at end of (passing) WorkflowTest.executorStepRestart in 1.596.1:
Exception in thread "Executor #0 for slave0 : executing PlaceholderExecutable:job/demo/1/:null" java.lang.NullPointerException
	at hudson.model.Computer.removeExecutor(Computer.java:869)
	at hudson.model.Executor.run(Executor.java:272)

Squashed commits:
[73308b5] [FIXED JENKINS-27549] job loading can be broken by a NPE in a build trigger