Bloomberg Tesla Inc is making plans to resume double shifts at its factory in Shanghai as soon as mid-May as it expects staffing and parts shortages to ease, according to people familiar with the matter. The US electric carmaker’s China factory was shuttered for three weeks in April as Shanghai was plunged into lockdown in an attempt to halt community spread of Covid-19. The plant started up again in late April under a so-called closed loop system whereby workers live on site and are tested regularly. The workers in that system have been doing 12-hour shifts, six days a week….