Part of issue888.

Thanks! I don't think another review is necessary, we can easily add/remove
configs later.

Looks good to me, but I only checked superficially. If this is a problem,
perhaps ask someone else to have a look, too.

I made a pull request at
https://bitbucket.org/jendrikseipp/downward/pull-requests/123 .

I added the configurations that we tested for issue213 (32-bit vs. 64-bit) and
removed the portfolios, which are tested by the driver tests already. Adding LP
configs is a bit more complicated since we don't have an LP solver on many
buildbots and on Bitbucket Pipelines, so I added the configs, but didn't include
them in any tests for now. We should discuss how to test them in issue888.

As a simple sanity check, we currently test on the Buildbot and on Bitbucket
pipelines that a set of planner configurations is able to solve some simple
planning tasks. In this issue we'd like to update the set of tested planner
configurations.