with Native Bullet, debug mesh ignores scaling of CollisionShape

[stephengold]

When Native Bullet is used with setDebugEnabled, scaled shapes are rendered as if they were unscaled. This can be demonstrated by modifying TestPhysicsRayCast to add the model (and a light source) to the scene:

        Spatial s = assetManager.loadModel("Models/Elephant/Elephant.mesh.xml");
        s.setLocalScale(0.1f);
        rootNode.attachChild(s);
        AmbientLight l = new AmbientLight();
        rootNode.addLight(l);

With this mod, it's clear that the debug visualization of the rigid body doesn't match the model. But if the model's local scale is set to 1, or if JBullet is used, the visualization matches the model.

The bug seems to be in DebugShapeFactory.getDebugMesh(), which populates a mesh based on an unscaled shape, expecting that the scale will be applied later. However, that scale never gets applied.

[stephengold]

The shape's scale gets applied in BulletRigidBodyDebugControl.update(). I suspect the model in TestPhysicsRayCast has a compound shape, which is a tricky case for scaling.

[stephengold]

Tested by modifying TestPhysicsRayCast as described above. Looks good with both jBullet and native Bullet.