Freeze pork until firm, about 20 minutes. Cut pork into 1/4-inch by 2- or 3-inch strips. Set aside.
Drain juice from pineapple into a small bowl, reserving pineapple. Add Worcestershire sauce and cornstarch to juice. Season with salt and pepper, if desired. Set aside.
In wok, heat 2 teaspoons oil over high heat. Add pork and stir-fry until white. Add broccoli, carrot, onion, corn, and reserved pineapple. Stir-fry until broccoli and carrots are brightly colored, about 2 minutes. Transfer to plate. Set aside.
Add remaining 1 teaspoon oil to wok. Add garlic and ginger. Stir-fry until fragrant, about 10 seconds, taking care not to burn them. Stir pineapple juice mixture. Add to wok with meat mixture. Stir-fry until liquid has thickened and meat is cooked through, 2 to 3 minutes. Serve immediately.