WFLY-3805: JGroupsBroadcastGroupConfiguration Serialization Problem

Please someone take a look at this.
Ok, thanks. In the future if you need an upgrade in order to make a PR function correctly, please include the upgrade as part of the PR, or include a strong statement about that in the PR description so people know it can't be merged until the upgrade is ready.

It looks like we have a significant hole in our test coverage if this PR was able to pass the testsuite without the upgrade in place.