Improve test jar dependency resolution for multi-module scenario

[cherylking]

Taken from issue #1561 as a follow-up remaining issue - @scottkurz @lmsurpre

There should be a way to resolve the test artifact used in one module dependency but contained in another module with just a:
mvn liberty:dev -f parent.

There are two ways to deal with this issue:

1. Do a mvn install of the dependency first before running dev mode

2. Do a mvn test-compile liberty:dev -f parent

The problem with doing the install first is that you end up "stuck" with the previously-built version of the dependency artifact. You miss out on one of the whole values of dev mode.

The second one will work better, the problem is that it's simply not all that obvious that this is what you need to do.
It would be a nice story too from the perspective that it generally shouldn't be necessary to do a mvn install before a multi-module build.

Scott looked to see if there was a simple fix and there doesn't seem to be. It might even require a bit of a hack to make this work and to get the artifacts to resolve correctly within dev mode. Scott believes some of the artifact resolution actually is designed to behave differently in the compile phases (which we don't participate in doing just mvn liberty:dev).