A 2-year-old boy who had crawled out of his Queens apartment through an open window and onto a fire escape fell six stories to his death yesterday morning. His mother had been taking a shower. Neighbors tried to comfort Ezquel Contreras, who was bleeding extensively and was later pronounced dead at Elmhurst Hospital. The neighbors also said that the child's mother, Sandra Perez, didn't seem to realize her son was gone, since she didn't come......