[JENKINS-13202] 646154f1 refinement: resolveSymlink is documented to return null, not throw an exception, when called on a regular file.

The bug was actually already fixed and moreover this could cause that fireCompleted won't be called in case that cleanUp throws an exception, see commentes under https://github.com/jenkinsci/jenkins/commit/51f715162eba4dd1c4e081ec15c7ceb12e813ca5

Added link to the pull request of "Changed defaults for the Mac installer to make iOS codesigning easier"

[FIXED JENKINS-15733] ArrayIndexOutOfBoundsException from Launcher due to misinterpretation of ProcStarter.envs in f5cebdc8.
(Should this field be made a [LinkedHash]Map<String,String> or even EnvVars?
It is protected in a final class, so effectively package-private, thus not a b/w compat issue.)

maven-failsafe-plugin deserves the same level of integration
as maven-surefire-plugin.

A failed IT should mark the build as unstable, not failed.

Integrated the fix made in Winstone.

Integrated a fix made in Stapler.

This reverts commit c8e5cb93.

[FIXED JENKINS-15316] Harmless but noisy exception running builds on some Windows systems in non-English locale.
Falling back to just checking for ‘FileSystemException’ since detail message about missing required privilege may be translated.