VKalVrt, optimizations
Replace dynamic_cast with virtual call in a hotspot, remove trivial destructors.
Callgrind analysis locates hotspots in this dyanamic_cast code, where 500 events called 100 Million of these dynamic casts. A virtual call is faster than a dynamic_cast.
Combined with the changes in !27919 (merged) this improves VKalVrt performance ~13% without changing output (checked BPHY5 BPHY8).
cc @wwalko