[test] Fixed JMX monitoring tests.
[test] Fixed JMX monitoring tests.

- Some tests where running without an associated CrateLayer.
- Check for exception on jmx query and fail.

EvilMcJerkface/crate,crate/crate,EvilMcJerkface/crate,crate/crate,crate/crate,EvilMcJerkface/crate