ONE Bryant Park Hotel guest got a surprise greeting when he returned to his room Thursday night to find Serena Williams’ two tiny pooches napping on his bed. “Serena checked into a suite with a terrace, and the guest staying next door to her left his door open a crack,” said our snitch. “When he returned to his room, he was greeted by Serena’s two dogs sleeping on his bed.” It seems the pups jumped the planter box sepa rating the terraces and squeezed into the other guest’s room. Luckily, they didn’t leave any other surprises behind.