war/src/test/js/ apparently produces war/target/surefire-reports/JasmineReport.xml without the TEST- prefix used by Surefire.

Obsolete with Java 8. Permanent generation was removed.

* Reference redirectors and jenkins.io as much as possible

* Something went wrong, so this is a troubleshooting URL

* More specific redirect URLs

This will allow PRs to resolve failing tests on Windows

This code can come back, IMO, after @svanoort and I fix the unpleasant/broken
tight-coupling between this Jenkinsfile and Groovy code floating around in the
jenkinsci/packaging repository

This needs to be reworked a bit to accomodate more modern versions of Jenkins
Pipeline

After https://github.com/github/linguist/pull/2861 we should not need the shebang for syntax highlighting.

Memory issues (suspected) are causing hanging test execution when
building/testing with JDK7u80, so at Daniel Beck's suggestion, let's
move to JDK8.

Now that we're using sh2ju for installer tests and not failing the
build for test failures, instead going unstable, let's re-enable
installer tests for 2.0.

BuildDiscarderProperty was moved to core from Pipeline, but not in
time for the 1.642 LTS line. So you need to explicitly use the fully
qualified class name when using it as long as you might be running on
1.642 or earlier LTSes.

The tests have a tendency to hang badly and don't pass in the first
place, so disabling them for now.

Some hacks in here to deal with building as root.