Find supported JVMs for remote agent attachment

[eyalkoren]

eg https://discuss.elastic.co/t/automatic-setup-problem/169789
We need to test at least each major distribution of each major version.

[eyalkoren]

Add tests relying on base JDK docker images. Since each image probably has only single JDK installed, testing self attachment (attach API) is practically the same as testing remote attachment.
Additional testing would include different OSs and remote attachment where attaching JVM is different than attached JVM