Preserve RegExp objects when copying the AST.
Preserve RegExp objects when copying the AST.

kassens/recast,kyldvs/recast,stefanpenner/recast,cpojer/recast,fkling/recast,benjamn/recast,benjamn/recast,shumov/recast,marcioj/recast,ersengultepe/recast,rwaldron/recast,benjamn/recast,ipeychev/recast