The test found out that RunMap's subMap implementation only returns loaded builds, so we needed to introduce a method to test if there was a specific run on the disk. For the weather reports we do not care if the record on the disk fails to load

Optimization for recent build stability calculation that should at most load two builds into memory for the recently stable case. In the non-recently stable case we just pre-load the most recently stable one and skip loading any intermediary successful ones

[FIXED JENKINS-27530] Jenkins.reload must also reload the Queue to ensure that every Queue.Item.task corresponds to a live Job, lest nextBuildNumber be bogus.

so that it can be used as below:

    try (BulkChange bc = new BulkChange(o)) {
       ...
       bc.commit();
    }

* [JENKINS-25164] Add SHORT_JOB_NAME env var

* Delete strip off

* [JENKINS-25164] Change SHORT_JOB_NAME for LEAF_JOB_NAME

* [JENKINS-25164] Change LEAF_JOB_NAME for JOB_BASE_NAME

- Code that is running from a plugin and on the master's JVM is guaranteed to never get null from this method (any cases where you do get null are bugs in core)
- Code that is running from a plugin and on a remote JVM should never be allowed to load the Jenkins class in their classloader, so should never use Jenkins.getInstance()... we are annotating the method with @Nullable so that such code can have some evolution time
- Code that is running in core and on one of two special paths should use the Jenkins.getInstanceOrNull() method so that the UI can be presented to users before the singleton has been instantiated / after the singleton has been destroyed
- The remaining 95% of uses in core (and 100% of uses in plugins) can safely assume that the instance is never null

This reverts commit bb7c8fce.

Closes #2090, I'll redo this as a PR... though if that PR is subject to multiple rounds of review before being merged then I will take that of evidence of the exact problem that committing directly was supposed to resolve... namely exponentially multiplying the effort required to make actual improvements to the code base.

Noting that there is a potentially valid argument for allowing this method to work without the singleton...

- But the type of tests here would be very restricted in what they could safely do anyway, so they would largely be restricted to verifying data migration during xml loading

- It is never too late to do the right thing.
- The vast majority of usages of `Jenkins.getInstance()` in core currently assume that its return value is non-null
- This commit changes those that are written to correctly check for non-null values will call `Jenkins.getInstanceOrNull()`
- We deprecate the `Jenkins.getActiveInstance()` madness
- I checked with @kohsuke who said not to bother with a PR and just commit this strongly opinionated change direct to master as a PR will just degrade into a bikeshedding.

If a job is renamed to a string with trailing whitespace, exceptions are
thrown as the application attempts to rename the job directory in the
file system, and the job can be neither deleted nor renamed again
through the UI. This problem occurs only when renaming a job, and not
when initially creating a job, because job names are trimmed when first
created.  This change trims the job name for rename operations as well,
so that the name-setting behavior is consistent across create/update
operations and inadvertent leading/trailing whitespace is removed before
it can cause problems.

#1406 silently skipped the call to moveDirectory in case newBuildDir.isDirectory(), rather than throwing an IOE as renameTo does.
Also deleting apparently useless call to forceMkdir.

(cherry picked from commit 9b3f4885)

Conflicts:
	changelog.html

Also sending the exception to the log, which is where plugin developers expect to see it.
(This is also necessary for the exception to be visible say from configRoundtrip in a functional test.
Otherwise you just see a FailingHttpStatusCodeException due to the 400 error code, with no details.)
Might actually suffice to just throw a ServletException wrapping the exception up the chain,
letting Stapler or the container handle it, but this change is more conservative.

Pulling doChildrenContextMenu up from AbstractProject into Job, since the latter already defines permalinks.

Moved configuration of keepDependencies into AbstractProject/configure-common.jelly, since it is not a property of Fingerprinter.

Undeprecating Job.getBuild, since this is the only way to look up a build by ID if you are unsure what kind of Job it is.

Null check the 'properties' element of the json message before attempting to 'rebuild' the 'DescribableList'

Cf.: https://github.com/jenkinsci/subversion-plugin/pull/83

java.lang.NullPointerException
	at hudson.model.Job.getBuildDir(Job.java:790)
	at hudson.model.Run.getRootDir(Run.java:993)
	at hudson.model.Run.getLogFile(Run.java:1306)
	at hudson.model.Run.execute(Run.java:1664)
	at hudson.maven.MavenBuild.access$900(MavenBuild.java:94)
	at hudson.maven.MavenBuild$ProxyImpl2.close(MavenBuild.java:636)
	at hudson.maven.AbstractMavenBuilder.end(AbstractMavenBuilder.java:106)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:839)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:523)
	at hudson.model.Run.execute(Run.java:1688)
	at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:519)
	at hudson.model.ResourceController.execute(ResourceController.java:88)
	at hudson.model.Executor.run(Executor.java:231)
java.lang.NullPointerException
	at hudson.model.BuildStepListener.all(BuildStepListener.java:31)
	at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:739)
	at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:714)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.cleanUp(MavenModuleSetBuild.java:1054)
	at hudson.model.Run.execute(Run.java:1733)
	at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:519)
	at hudson.model.ResourceController.execute(ResourceController.java:88)
	at hudson.model.Executor.run(Executor.java:231)

[FIX JENKINS-21303] There is a NPE here that can and does happen for real when an aggresive slave retention strategy interacts with post build triggers that want to do token macro expansion

unbuildable project.

Added a new overloaded version that works on a project.

Updated CoreEnvironmentContributor accordingly.