NORTH COAST — The high-end part of the wine industry will start to recover by the end of this year, with revenue growth this year for wines retailing for more than $20 a bottle of 8 percent to 12 percent from that of last year, according to an economic forecast released today by Silicon Valley Bank. The “muted and long process” of economic recovery will come this year as the nearly two-year luxury consumer “trading down” trend to less-expensive wines reverses, distributors halt deep discounts of higher-end wines in the third quarter and trade sales channels restock, according to report author Rob McMillan, founder of the bank’s premium wine division.