Oxygen development is limited by SingleFeatureTest running out of heap space

SingleFeatureTest is failing on odl-integration-all feature for some contributions, preventing them from merging (as distribution-check fails).

As reported in e-mail [0], there is a workaround (Distribution to set higher heap size in order for SingleFeatureTest to pass), which just needs Odlparent releasing 2.0.5 version.

Local testing showed this might be just a consequence of ODLPARENT-115 Karaf 4.0.9 consumes not only time but also memory in excess. But it might be possible to fix memory consumption in a different way.

Also, this Bug is more severe than ODLPARENT-115 as that has a workaround of just waiting for a longer time.

Additional example of a Change failing distribution-check: [1].

[0] https://lists.opendaylight.org/pipermail/odlparent-dev/2017-September/001341.html
[1] https://git.opendaylight.org/gerrit/63329