This algorithm will mutate an array of whole numbers equally, so that the new array sum is equal to the inputed sum.
Example:
let numbers = [ 1, 2, 3, 4, 5, 6, 7 ];
let sumChange = arraySumChanger(50, numbers);
console.log(sumChange)
// expected ouput: [ 5, 5, 6, 7, 8, 9, 10 ]