修复box2d 内存泄漏问题

cocos/physics-2d/box2d-wasm/physics-contact.ts

@@ -97,9 +97,10 @@ export class PhysicsContact implements IPhysics2DContact {
     }
 
     init (b2contact: number): void {
-        const ab = B2.ContactGetFixture(b2contact) as Vec2;
-        this.colliderA = (getTSObjectFromWASMObjectPtr<B2Shape2D>(B2ObjectType.Fixture, ab.x)).collider;
-        this.colliderB = (getTSObjectFromWASMObjectPtr<B2Shape2D>(B2ObjectType.Fixture, ab.y)).collider;
+        const fixtureA = B2.ContactGetFixtureA(b2contact) as number;
+        const fixtureB = B2.ContactGetFixtureB(b2contact) as number;
+        this.colliderA = (getTSObjectFromWASMObjectPtr<B2Shape2D>(B2ObjectType.Fixture, fixtureA)).collider;
+        this.colliderB = (getTSObjectFromWASMObjectPtr<B2Shape2D>(B2ObjectType.Fixture, fixtureB)).collider;
         this.disabled = false;
         this.disabledOnce = false;
         this._impulsePtr = 0;

cocos/physics-2d/box2d-wasm/shapes/box-shape-2d.ts

@@ -70,4 +70,11 @@ export class B2BoxShape extends B2Shape2D implements IBoxShape {
         B2.PolygonShapeSetAsBoxWithCenterAndAngle(shape, width, height, offsetX, offsetY, 0);
         return [shape];
     }
+
+    destroy (): void {
+        for (let i = 0; i < this._shapes.length; i++) {
+            B2.PolygonShapeDelete(this._shapes[i]);
+        }
+        super.destroy();
+    }
 }

cocos/physics-2d/box2d-wasm/shapes/circle-shape-2d.ts

@@ -56,4 +56,11 @@ export class B2CircleShape extends B2Shape2D implements ICircleShape {
 
         return [shape];
     }
+
+    destroy (): void {
+        for (let i = 0; i < this._shapes.length; i++) {
+            B2.CircleShapeDelete(this._shapes[i]);
+        }
+        super.destroy();
+    }
 }

cocos/physics-2d/box2d-wasm/shapes/polygon-shape-2d.ts

@@ -112,4 +112,11 @@ export class B2PolygonShape extends B2Shape2D implements IPolygonShape {
 
         return shapes;
     }
+
+    destroy (): void {
+        for (let i = 0; i < this._shapes.length; i++) {
+            B2.PolygonShapeDelete(this._shapes[i]);
+        }
+        super.destroy();
+    }
 }