By Nichola Saminather TORONTO (Reuters) -Sun Life Financial shares jumped on Thursday after reporting a better-than-expected second-quarter profit and announcing the sale of its U.K. business as well as an asset management partnership with the buyer, Phoenix Group Holdings. Earlier on Thursday, Canada’s second-largest life insurer agreed to sell its closed business in the United Kingdom to Phoenix for 248 million pounds ($301 million), and become its strategic asset management partner, managing about C$9 billion ($7 billion) of Sun Life UK’s general account. Sun Life expects to get a “good chu…