Tesla has managed to expand its electric-car marketshare, despite two new battery-powered luxury SUVs that have been in U.S. showrooms for the last 10 months: Jaguar’s I-Pace and Audi’s e-tron. Bloomberg reports: Their starts are the latest indications that legacy automakers aren’t assured instant success when they roll out new plug-in models. Tesla’s Model S and X have largely held its…