Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.

Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value 3, the linked list should become 1 -> 2 -> 4 after calling your function.

Tips：刪除鏈表中的一個結點，但是僅給出一個需要刪除的鏈表。

解決思路：將要刪除的結點node的後一個結點的val賦值給要node，再刪除node.next。

public void deleteNode(ListNode node) {
            if(node==null ||node.next==null){
                return ;
            }
            node.val=node.next.val;
            node.next=node.next.next;
        }

【Leetcode】237. Delete Node in a Linked List