Write a method named secondIndexOf that returns the index of the second occurrence of a particular value in an array of integers.
If the value does not appear in the array at least twice, you should return -1.
For example, if an array called list stores the following values:
// index 0 1 2 3 4 5 6 7 8 9 10
int[] list = {42, 7, -9, 14, 8, 39, 42, 8, 19, 0, 42};
Then the call secondIndexOf(list, 42) should return 6 because the index of the second occurrence of value 42 in the array is at index 6.
The call secondIndexOf(list, 14) should return -1 because value 14 does not occur at least twice in the array.
