“SNL’’ cast member Kate McKinnon isn’t the only one who does a Hillary Clinton impression. Pro wrestler and West Newbury native John Cena, cohosting Sunday’s Teen Choice Awards, donned a fuscia pantsuit and an impressive wig to poke fun at the Democratic presidential candidate. Cena’s cohost Victoria Justice played Donald Trump. Neither could compare to Keegan-Michael Key, who did a bit of his spot-on impression of President Obama.