MILAN (Reuters) - European shares remained stuck in a "Santa Crash" on Tuesday in a fourth straight session of losses, dragged down by poor economic data and lower oil prices. The pan-European STOXX 600 index ended the day down 0.6 percent, just a few points away from two-year lows hit last week on slowing economic growth worries.A vast majority of European bourses and sectors traded in the red and didn't recover when the S&P 500 and the Nasdaq opened higher after the previous session's..