Change the arena's chunk tree from a splay tree to an ordinary tree (so that it's not possible to accidentally splay it and leave it unbalanced).
New function TreeFindNext allows us to implement TractFirst and TractNext without having to splay the tree.
Make sure all operations on the chunk tree leave it balanced. But don't balance the tree directly in ChunkFinish() because this is only ever called in a loop where multiple chunks are being deleted from the tre. Instead use the sequence TreeToVine -- iterate and delete -- TreeBalance. The new macro TREE_DESTROY assists with this.
No need any more for ArenaIsReservedAddr, CHUNK_OF_ADDR, TRACT_OF_ADDR.
Update design documentation.
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Change: 186212
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Balance the chunk tree after insertion and deletion.
Avoid calling TractFirst and TractNext in ArenaDescribeTracts and PoolOfRange.
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Change: 186199
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Using TREE_ELT where appropriate.
Using AVERT consistently on Tree, but see job003691.
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Change: 184724
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Updating Splay Tree design document to be reasonably consistent with the current code.
Disabling tree functions not currently in use.
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Change: 184723
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