Declarative Jenkins pipeline
Currently all the jenkins build jobs are generated by the DSL job from the cassandra-builds repository.
For a given branch, there are numerous builds: artifacts, unit tests, and dtests.
Using a (declarative) Jenkinsfile in-tree these builds can be put together into per-branch pipelines.
Per-branch pipelines will give a nicer UI (via blue ocean) and one place to look at test results for any branch and commit. From there we can post one complete test summary on commits back to the related jira ticket.
Removing `ant test-all`
Currently the test-all target does nothing but execute the test target.
This is because the test targets finishes with unit test failures.
As these jenkins jobs are automated here: https://github.com/apache/cassandra-builds/blob/master/jenkins-dsl/cassandra_job_dsl_seed.groovy#L44 ; it is easy enough to remove the "test-all" target, replacing it with separate jobs for 'stress-test', 'fqltool-test', and 'long-test'.