Given two binary search trees root1 and root2, return a list containing all the integers from both trees sorted in ascending order.
Input: root1 = [2,1,4], root2 = [1,0,3]
Output: [0,1,1,2,3,4]
Input: root1 = [1,null,8], root2 = [8,1]
Output: [1,1,8,8]
The number of nodes in each tree is in the range [0, 5000].
-10^5 <= Node.val <= 10^5