The Olympics have long been an almost ideal forum for companies looking to promote themselves, with plenty of opportunities for brands to nestle ads among the pageantry and feel-good stories about athletes overcoming adversity — all for less than the price of a Super Bowl commercial.But now, as roughly 11,000 competitors from more than 200 countries convene in Tokyo as the coronavirus pandemic lingers, Olympic advertisers are feeling anxious about the more than $1 billion they have spent to run ads on NBC and its Peacock streaming platform.Calls to cancel the more than $15.4 billion extravaganza have intensified as more athletes test positive …