Costumed actors take your tickets, will for a modest amount pour you a glass of wine, and engage in gorgeous and intriguing dance-like interactions in front of a stunning backdrop of silky delicately-toned hangings.   It makes you sure you’re in for great theater.  Once Sarah Flood in Salem Mass starts, though, the fun dissipates.   With its reference to the Salem Witch Trials, the play takes on the trappings of seriousness but flings itself into making a jumble of the actual events and persons;  that could be OK, except that it offers no thoughts or ideas in return for its use of this tragic historical episode and the multitudes who suffered hideously because of it.