* Avoid manual handling of previous sapling trees by using iterator windows instead
* Avoid manual sapling subtree index handling by comparing prev and current subtree indexes instead
* Simplify adding notes by using the exact number of remaining notes
* Simplify by skipping the first block, because it can't complete a subtree
* Re-use existing tree update code
* Apply the sapling changes to orchard subtree updates
* add a reverse database column family iterator function
* Make skipping the lowest tree independent of iteration order
* Move new subtree checks into the iterator, rename to end_height
* Split subtree calculation into a new method
* Split the calculate and write methods
* Quickly check the first subtree before running the full upgrade
* Do the quick checks every time Zebra runs, and refactor slow check error handling
* Do quick checks for orchard as well
* Make orchard tree upgrade match sapling upgrade code
* Upgrade subtrees in reverse height order
* Bump the database patch version so the upgrade runs again
* Reset previous subtree upgrade data before doing this one
* Add extra checks to subtree calculation to diagnose errors
* Use correct heights for subtrees completed at the end of a block
* Add even more checks to diagnose issues
* Instrument upgrade methods to improve diagnostics
* Prevent modification of re-used trees
* Debug with subtree positions as well
* Fix an off-by-one error with completed subtrees
* Fix typos and confusing comments
Co-authored-by: Marek <mail@marek.onl>
* Fix mistaken previous tree handling and end tree comments
* Remove unnecessary subtraction in remaining leaves calc
* Log heights when assertions fail
* Fix new subtree detection filter
* Move new subtree check into a method, cleanup unused code
* Remove redundant assertions
* Wait for subtree upgrade before testing RPCs
* Fix subtree search in quick check
* Temporarily upgrade subtrees in forward height order
* Clarify some comments
* Fix missing test imports
* Fix subtree logging
* Add a comment about a potential hang with future upgrades
* Fix zebrad var ownership
* Log more info when add_subtrees.rs fails
* cargo fmt --all
* Fix unrelated clippy::unnecessary_unwrap
* cargo clippy --fix --all-features --all-targets; cargo fmt --all
* Stop the quick check depending on tree de-duplication
* Refactor waiting for the upgrade into functions
* Wait for state upgrades whenever the cached state is updated
* Wait for the testnet upgrade in the right place
* Fix unused variable
* Fix a subtree detection bug and comments
* Remove an early reference to reverse direction
* Stop skipping subtrees completed at the end of blocks
* Actually fix new subtree code
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Co-authored-by: Marek <mail@marek.onl>