Add test case that checks whether a solver does not only support
multiple stacks, but also has "global declarations"
that do not get deleted on pop().
Without this, multiple stacks do not make sense for us.

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/trunk@14682 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c