perf: Make CacheKV store interleaved iterator and insertion not O(n^2…

…) (backport cosmos#10026) (cosmos#10167)

* perf: Make CacheKV store interleaved iterator and insertion not O(n^2) (cosmos#10026)

(cherry picked from commit 28bf2c1)

# Conflicts:
#	CHANGELOG.md
#	store/cachekv/store.go

* fix changelog conflict

* Update store.go

Co-authored-by: Dev Ojha <ValarDragon@users.noreply.github.com>
Co-authored-by: Robert Zaremba <robert@zaremba.ch>

CHANGELOG.md

@@ -38,7 +38,9 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ## [Unreleased]
 
 ### Improvements
+
 * (types) [\#10021](https://github.com/cosmos/cosmos-sdk/pull/10021) Speedup coins.AmountOf(), by removing many intermittent regex calls.
+* (store) [\#10026](https://github.com/cosmos/cosmos-sdk/pull/10026) Improve CacheKVStore datastructures / algorithms, to no longer take O(N^2) time when interleaving iterators and insertions.
 
 ### Bug Fixes