Update directory

Author: siriak

DIRECTORY.md

@@ -856,7 +856,6 @@
               * [QueueByTwoStacksTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueByTwoStacksTest.java)
               * [QueueTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/queues/QueueTest.java)
             * stacks
-              * [LinkedListStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/LinkedListStackTest.java)
               * [ReverseStackTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java)
               * [StackArrayListTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayListTest.java)
               * [StackArrayTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/datastructures/stacks/StackArrayTest.java)