Constellation stock is up! No, it’s down! Wait, who’s right? Turns out, they both are. In an unusual bit of symmetry, shares of two companies named “Constellation” are among both the S&P 500’s top gainers and losers Friday.  On the green side of the ledger is Constellation Energy (CEG), shares of which were recently up some 26%. That was good for the second-best performance in the benchmark index after Walgreens Boots Alliance (WBA). Driving the move was the news that the company agreed to buy privately ow ...