Faster LinkedHashMap tail() (#2725)

Change: LinkedHashMap tail() is now constant-time, from being O(size)
time and space.

Motivation: We have a use case which looks somewhat like the following.

1. It's effectively a Queue use case (fifo).
2. Iteration order needs to be stable.
3. Elements in the queue frequently need to be verified as present in
   the queue.
4. Occasionally, removals must occur, which are usually from the head of
   the queue although occasionally randomly.

We started with a Queue and eventually found performance issues from too
much linear scanning. This was not obviously going to be a bottleneck
since our queues are usually of very small size, but ended up so.
The next type we considered was a LinkedHashSet, using the `head` and
`tail` methods to implement a dequeue-like operation and the set
operations being sufficient for the other operations. Unfortunately,
it seems that `tail` at present copies the entire queue despite not
seemingly needing to.

We moved to our own hand-crafted HashSet+Queue structure, but this PR
seems like it'd generally be beneficial for users of Vavr!

Author: j-baker

src/main/java/io/vavr/collection/LinkedHashMap.java

@@ -917,7 +917,7 @@ public LinkedHashMap<K, V> tail() {
         if (isEmpty()) {
             throw new UnsupportedOperationException("tail of empty LinkedHashMap");
         } else {
-            return LinkedHashMap.ofEntries(list.tail());
+            return wrap(list.tail(), map.remove(list.head()._1()));
         }
     }