Holiday earnings forecasts are disappointing investors so far, and the biggest boxes under Wall Street’s tree are coming this week. So far in earnings season, a dozen S&P 500 SPX, -0.11 companies have issued earnings guidance, and eight of them have come in lighter than expected. Investors have punished those companies — such as Intel Corp.Health INTC, -11.68, which had its worst day in more than a year Friday following a weak forecast — as well as those outside the index that have disappointed, such as Snap Inc. SNAP, -26.59, which lost nearly a quarter of its market capitalization Friday. The market can withstand those kinds of moves from a…