SAN FRANCISCO :How can Tesla become an $8.5 trillion company? That's the market valuation the electric vehicle maker would have to reach to justify CEO Elon Musk's new pay package announced last week.    Selling 100 million humanoid robots in a year could do it; creating a robotaxi network with more than 10 times the revenue of Uber might as well. And of course, investor hope is part of the equation.  Musk on Friday was given a decade to expand Tesla's $1 trillion valuation into a company worth