U.S. stock index futures rose on Tuesday as an upbeat profit forecast from Johnson & Johnson added to the positive momentum in corporate earnings generated by big banks last week. Johnson & Johnson’s shares rose 1.7 percent after it raised its 2021 adjusted profit forecast, even as it stuck to its outlook of $2.5 billion in sales from its COVID-19 vaccine this year. Walmart Inc.’s shares rose 2 percent after Goldman Sachs added the world’s largest retailer to its “Americas Conviction List.” Large-cap technology and communications companies including Facebook Inc., Apple Inc., Amazon.com Inc., Alphabet Inc., and Microsoft Corp. all rose between 0.3 percent and 0.7 percent. Netflix Inc. rose 0.1 percent ahead of its quarterly results later in the day. After forecast-beating results from big banks last week set a positive tone for this earnings season, investors now turn to results from companies that are more exposed to supply …