Remove redundant type check

The same condition is repeated twice (caught by FindBugs.)

src/main/javassist/util/proxy/SecurityActions.java

@@ -213,7 +213,6 @@ static TheUnsafe getSunMiscUnsafeAnonymously() throws ClassNotFoundException
             if (e.getCause() instanceof NoSuchFieldException)
                 throw new ClassNotFoundException("No such instance.", e.getCause());
             if (e.getCause() instanceof IllegalAccessException
-                    || e.getCause() instanceof IllegalAccessException
                     || e.getCause() instanceof SecurityException)
                 throw new ClassNotFoundException("Security denied access.", e.getCause());
             throw new RuntimeException(e.getCause());