Experiment: latest-state existence filters on `mmap`

`bloatnet`, `performance` git branch

instead of copy into Erigon's RAM (fastest, but ram-greedy approach): try `madv(willneed)` on Existence filters (test only for Commitment.Domain - probably enough but it's up to you). My intuition tells that it will crazy-increase disk-read-IO

`DOMAIN_EXISTENCE_MEM=false DOMAIN_EXISTENCE_WILLNEED=true`

Use Grafana and "same blocks range execution" to compare speed

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Context:
- We did `madv(random)` for existence filters in the past: and it 2x reduced performance compare to `copy in Erigon's ram`