Add a new configuration option to the LiveVariablesTransferRelation that lets the user choose if global variables should be assumed as being live or not. Adapted all configurations to use the appropriate value for this option.

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/trunk@14681 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c