HOUSTON — By around 4:15 p.m. Sunday afternoon, the Miami Dolphins will prove whether they’re formidable for a potential postseason run or flat-out undeserving. They have the opportunity to do something they have rarely done in coach Mike McDaniel’s tenure leading the franchise: Win a road game against a playoff-caliber opponent. That’s what’s in front of the Dolphins (6-7) as they face the AFC South-leading Texans (8-5) at Houston’s NRG Stadium in a 1 p.m.