Refactoring of the LiveVariables class, due to the changes in LocationCPA we don't need to create the live variables partially at different points of the CFACreator, instead we can do it in one Location after the computation of the variable classification.

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/trunk@14626 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c