edgePropertiesMap
We use this map to store additional information on the DFG edges which we cannot keep in the state. This is for example the case to identify if the resulting edge will receive a context-sensitivity label (i.e., if the node used as key is somehow inside the called function and the next usage happens inside the function under analysis right now). The key of an entry works as follows: The 1st item in the pair is the prevDFG of the 2nd item. If the 2nd item is null, it's obviously not relevant. Ultimately, it will be 2nd -prevDFG-> 1st.