The selloff in Tesla’s (TSLA) stock is worsening after the electric-vehicle maker reported delivery figures for this year’s first quarter that fell far short of Wall Street expectations. Tesla said that it delivered 386,810 vehicles in Q1, down nearly 9% from 423,000 a year earlier.It marks the worst year-over-year decline in the company’s vehicle deliveries ever. Analysts who cover Tesla had expected 425,000 electric vehicle deliveries for the quarter. Even the most pessimistic forecast called for more than 400,000 vehicles to be delivered in Q1. Tesla said that it produced 433,371…