LONDON — Rejected time and again for the 2022 Winter Olympics, the IOC will soon be seeking suitors for the 2024 Summer Olympics. It will be hoping to attract a competitive, high-profile field to show there are cities that want to host the games rather than shun them. Even before Oslo became the fourth city to drop out of the race for the 2022 Games, the International Olympic Committee had started reviewing its bidding system to make it more appealing and less expensive for future host cities.