Ten minutes separated the Chicago Cubs from the cusp of ending a season-high losing streak to their worst loss of the season. A five-run lead entering the bottom of the eighth should have provided enough cushion for the Cubs to put away the Houston Astros. Instead they departed Minute Maid Park ahead of Thursday’s day off with a crushing 7-6 walk-off loss that raised more questions about how the Cubs bullpen can get on track. The Cubs (19-24) head to Philadelphia, where they kick off the last leg of their three-city, nine-game trip Friday carrying a five-game losing streak. “We’ve got to cash that win in,” manager David Ross said.