After the gerrit update, we got a static LinuxSLES build as a part of the default precheck.

This revealed several problems with running QtPositioning unit-tests. Specifically, the special test plugins are not found, and so the tests that depend on them fail.

The scope of this task is to find out how other modules deal with this problem. If there is no easy solution, we can at least skip the problematic tests in the static build from the top-level CMakeLists.txt file, so that we do not block the CI.