Rinse out the wok and wipe it dry. Return it to high heat, add the remaining 1 tablespoon oil and swirl to coat the wok. Toss in the garlic and stir-fry until golden, about 30 seconds. Add the meat and stir-fry until it turns white, about 2 minutes. Add the greens and stir-fry until softened, 3 to 4 minutes. Add the remaining 2 tablespoons soy sauce, the fish sauce and mix well. Pour in the chicken stock and bring to a vigorous boil. Cook for 3 minutes. Add the dissolved cornstarch and cook, stirring, until the sauce thickens, about 2 minutes. Remove from the heat and pour over the noodles. Sprinkle the white pepper on top and serve in deep bowls. Pass the Vinegar-Chile Sauce separately.