java-decompiler: post-import cleanup (common fixes and optimizations)

src/org/jetbrains/java/decompiler/util/InterpreterUtil.java

@@ -83,9 +83,8 @@ public class InterpreterUtil {
       return false;
     }
 
-    HashSet<?> set = new HashSet(c1);
+    HashSet<Object> set = new HashSet<Object>(c1);
     set.removeAll(c2);
-
     return (set.size() == 0);
   }