MANILA, Philippines — The Philippine defense chief condemned China’s deployment of a swarm of armed coast guard forces, backed by a helicopter and a drone, closer to the Philippines’ military outpost in a fiercely disputed atoll in the South China Sea. Its military also vowed to defend the offshore territory, the scene of repeated, tense faceoffs. The latest flare-up in the long-seething territorial disputes around the Second Thomas Shoal came up in closed-door talks between Philippine Defense