Fixed a concurrent issue

Author: terminalsin

dev.skidfuscator.obfuscator/src/main/java/dev/skidfuscator/obf/skidasm/SkidGraph.java

@@ -99,7 +99,7 @@ public void postlinearize(final ControlFlowGraph cfg) {
             next = immediate;
         }*/
 
-        for (BasicBlock vertex : cfg.vertices()) {
+        for (BasicBlock vertex : new HashSet<>(cfg.vertices())) {
             if (vertex instanceof FakeBlock)
                 continue;