Reduce complexity of control dependency computation

src/main/java/tfm/graphs/Graph.java

src/main/java/tfm/graphs/augmented/ACFG.java

src/main/java/tfm/graphs/augmented/ACFGBuilder.java

src/main/java/tfm/graphs/cfg/CFG.java

src/main/java/tfm/graphs/cfg/CFGBuilder.java

src/main/java/tfm/graphs/pdg/ControlDependencyBuilder.java

src/main/java/tfm/graphs/pdg/DirectedTree.java

src/main/java/tfm/graphs/pdg/PDGBuilder.java

src/main/java/tfm/graphs/pdg/PostdominatorTree.java

src/main/java/tfm/nodes/GraphNode.java