Preheat oven to 425°. Combine potatoes and butternut squash in an 11 x 7-inch baking dish. Combine 1 tablespoon olive oil, thyme, sage, 1/2 teaspoon salt, and pepper; toss with vegetables. Roast at 425° for 15 minutes. Heat a large skillet over medium-high heat. Add 1 tablespoon olive oil. Sprinkle pork tenderloin with 1/2 teaspoon salt. Add pork to pan; sauté 4 minutes. Stir vegetables; add pork and sherry. Roast for 12 minutes or until a thermometer registers 145°. Remove pork; let stand 5 minutes.