track zero lamport accounts (#3188)

* track zero lamport accounts

split off slot from shrink ancient stats

split slot stat

* populate zero lamport at start time

* pub

* comments

* comments

* pr fix

* fix

* test zero single ref init

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* pr feedback reanem

* pr feedback outline fn

* pr: rename

* pr: rename

* pr: rename

* clippy

* fix stat

* no check for zero_lamport_single_ref_found

* num_slots_with_zero_lamport_accounts_added_to_shrink

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* pr feedbacks

* rename

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* pr

* pr

* pr

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* fix build

* Update accounts-db/src/accounts_db.rs

Co-authored-by: Brooks <[email protected]>

* pr

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Co-authored-by: HaoranYi <[email protected]>
Co-authored-by: Brooks <[email protected]>