GLOBAL MARKETS-Stocks rebound as Ukraine jetliner tensions ease

* Risk appetite rises on cooperation with Ukraine separatists * S&P 500 sets new intraday high, European shares surge * Dollar gains as euro sinks to eight-month low (Adds oil settlement prices) By Herbert Lash NEW YORK, July 22 (Reuters) - Global equity markets and the dollar rode a rebound in risk appetite on Tuesday that lifted the S&P 500 to a record high on signs of cooperation from Ukraine's pro-Russian separatists over last week's downing of a Malaysian jetliner. Ben