SAN FRANCISCO — As Amazon, Microsoft and Google race ahead in artificial intelligence, they are trying to avoid antitrust scrutiny by stopping short of buying hot companies outright and instead investing in them, hiring their top engineers or licensing their technologyA self-described whistleblower is now arguing to regulators that Amazon played it too close, illegally disguising what was effectively an acquisition because it was liable to be blocked, according to his filing obtained by The Wash...