1beea7a [wallet] Make CWallet::ListCoins atomic (João Barbosa)
Pull request description:
Fix a potencial race in `CWallet::ListCoins`. Replaces `cs_main` and `cs_wallet` locks by assertions in `CWallet::AvailableCoins`.
Backport of Core PR12333
Note: 2f960b5 [wallet] Indent only change of CWallet::AvailableCoins (João Barbosa) was skipped because our linter made the changes unnecessary. I also verified that cherry-picking this commit resulted in no change to the code.