San Francisco’s Wells Fargo, the nation’s largest home lender, posted a 19 percent increase in second-quarter profit as it overcame an easing in the mortgage market on its way to record earnings. The results, helped by falling expenses and growth across the bank’s deposit and lending business, included net income of $5.5 billion, or 98 cents a share. That compared with $4.6 billion, or 82 cents, a year earlier. Revenue, roughly flat at $21.4 billion, also exceeded expectations. But stock gains stayed in check as some investors see an easing in the mortgage market as a signal of a slowdown in the broader industry.