Check performance after Part7 restructuring

[rakita]

After this PR #1865 performance for snailtracer has degraded by 8%.
Part 6 #1814 (comment): I refs: 429,384,219
Part 7 #1865 (comment): I refs: 464,099,580

It is hard to tell where the change is as a lot of things got touched. Samply of latest code: https://share.firefox.dev/3VqdeZg

Would assume it is related to new Instruction that is now a Trait. There were changes to Stack that could potentially cause this. Or removal of generic SPEC from functions (it is now a runtime check).