Restore 0.8.x behavior where java driver is marked as detected when
`java -version` exits with 0 but returns unexpected output.

Furthermore, we restore behavior when `java -version` where we parse the
first three lines of `java -version` but ignore rest.

If `java -version` returns less than 3 lines, Nomad 0.8.7 would panic.
In this implementation, we'd still mark java as detected but returns
empty version.

The 0.8.7 logic for detecting java version is found in
https://github.com/hashicorp/nomad/blob/v0.8.7/client/driver/java.go#L132-L172
.

I punt on revamping how we can be more resilient to java -version
syntax, and aimed for preserving existing behavior instead.