HOUSTON — Power, then patience. On Saturday night, that was the winning formula for the Yankees. Austin Wells hit their third home run of the game, a go-ahead shot to lead off the seventh inning, before they added insurance runs on a pair of bases-loaded walks to secure the Yankees’ eighth straight win, 8-3 over the Astros at Daikin Park. Trent Grisham and José Caballero also went deep while Ryan Weathers became the latest starter to turn in a strong outing as the Yankees (18-9) matched their longest winning streak from last season. Over the first two games of this series, the Yankees have racked up 20 runs on 25 hits, ganging up on the brutal pitching staff of the Astros (10-18). With the game tied at 2 entering the seventh inning, the scuffling Wells finally delivered a big hit, homering off Kai-Wei Teng to put the Yankees ahead by a run. They then mounted a rally to create more breathing room.…