PersistentSlabStorage cache and deltas optimization

[bluesign]

Issue To Be Solved

I think PersistentSlabStorage cache and deltas can use map[uint64][uint64]Slab and can avoid extra hashing on cpu level. Especially for migration, this can be a speed up, as we have only 2 address options. ( zero and migrated address) and big accounts has a lot of Slabs.

Reference discord thread: https://discord.com/channels/613813861610684416/1108479699732152503/1254739545140891658

[fxamacker]

Hi @bluesign Thanks! This looks interesting!

I'll take a look after wrapping up diff-states comparisons. Currently focused on correctness before resuming optimizations.