During the boom years, Morgan Stanley’s vaunted real-estate investing unit bought trophy office buildings in San Francisco, a Boston development project, and glittering lodging properties like Hawaii’s Grand Wailea resort. These days, the Wall Street giant is scouring the fringes of the property market in the hunt for high returns. One of its recent deals: a half-empty 60,000-square-foot shopping center in California’s Inland Empire that houses a Fresh & Easy Neighborhood Market.