Implement `customPromiseAll(promises)` that mimics `Promise.all()`.
Example:
const p1 = Promise.resolve(1);
const p2 = Promise.resolve(2);
const p3 = Promise.resolve(3);
customPromiseAll([p1, p2, p3]).then(console.log); // [1, 2, 3]
const p4 = Promise.reject("Error");
customPromiseAll([p1, p4, p3]).catch(console.log); // "Error"