refactoring bam-transfer and bam-subtree-remover. for a special case of block-layout (exit-node equals call-node of next block, but next block is not nested in previous) there is an exception. however, this case was also handled wrong before (transfer went wrong).

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/trunk@13009 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c