Add violations for Lists.newCopyOnWriteArrayList() and Maps.newConcurrentMap()

Summary says it. Consideration mentioned in the commit message:

> Note that the behavior of `Maps.newConcurrentMap()` is slightly different from `new ConcurrentHashMap<>()`: with Guava 18.0 the former creates a map with a concurrency level of 4, whereas the latter uses concurrency level 16. Most users will not care, and those that do should make this intention explicit. (This is one of the reasons that the JavaDoc for Maps.newConcurrentMap points to MapMaker.)