Move some long tests out of short-test group
Some tests for eg 04-lithium take 1hr to run on valgrind builder see http://mpsd-octopus-code-staging.desy.de/buildbot/#/builders/178/builds/3/steps/7/logs/stdio. This MR moves them to long-test group in order to reduce the Valgrind builder time (which only runs short-test at the moment).
Move 04-lithium.test to long-test group