Fixed bug: cross chain edges are built using events exit points and functions entry points

Additionally, a CONSERVATIVE_LINK option has been added. If it is checked and there is no match between the event exit point and the function entry point, a conservative link is performed by connecting the corresponding LOG opcode with all the entry points of the bridge functions

Author: merendamattia

src/main/java/it/unipr/cfg/EVMCFG.java

@@ -92,7 +92,8 @@ public Set<Statement> getAllLogX() {
 			Set<Statement> logxs = new HashSet<>();
 
 			for (Statement statement : cfgNodeList.getNodes()) {
-				if (statement instanceof Log) {
+				if (statement instanceof Log1 || statement instanceof Log2 || statement instanceof Log3
+						|| statement instanceof Log4) {
 					logxs.add(statement);
 				}
 			}