Cycles: fully decouple triangle and curve primitive storage from BVH2

Previously the storage here was optimized to avoid indirections in BVH2
traversal. This helps improve performance a bit, but makes performance
and memory usage of Embree and OptiX BVHs a bit worse also. It also adds
code complexity in other parts of the code.

Now decouple triangle and curve primitive storage from BVH2.
* Reduced peak memory usage on all devices
* Bit better performance for OptiX and Embree
* Bit worse performance for CUDA
* Simplified code:
** Intersection.prim/object now matches ShaderData.prim/object
** No more offset manipulation for mesh displacement before a BVH is built
** Remove primitive packing code and flags for Embree and OptiX
** Curve segments are now stored in a KernelCurve struct
* Also happens to fix a bug in baking with incorrect prim/object

Fixes T91968, T91770, T91902

Differential Revision: https://developer.blender.org/D12766

intern/cycles/render/object.cpp

@@ -60,6 +60,7 @@ struct UpdateObjectTransformState {
 
   /* Packed object arrays. Those will be filled in. */
   uint *object_flag;
+  uint *object_visibility;
   KernelObject *objects;
   Transform *object_motion_pass;
   DecomposedTransform *object_motion;
@@ -528,6 +529,9 @@ void ObjectManager::device_update_object_transform(UpdateObjectTransformState *s
                                              (1.0f - 0.5f * ob->shadow_terminator_shading_offset);
   kobject.shadow_terminator_geometry_offset = ob->shadow_terminator_geometry_offset;
 
+  kobject.visibility = ob->visibility_for_tracing();
+  kobject.primitive_type = geom->primitive_type();
+
   /* Object flag. */
   if (ob->use_holdout) {
     flag |= SD_OBJECT_HOLDOUT_MASK;