refactor: Get rid of more redundant chain methods
Summary:
This just drops three interfaces::Chain methods replacing them with other calls.
Motivation for removing these chain methods:
- Need to get rid of findFirstBlockWithTimeAndHeight for #10102, which doesn't support overloaded methods
- Followup from https://github.com/bitcoin/bitcoin/pull/16426#discussion_r412487403
- phantomcircuit comments about findNextBlock test http://www.erisian.com.au/bitcoin-core-dev/log-2020-06-06.html#l-214
Behavior is not changing in any way here. A TODO comment in
ScanForWalletTransactions was removed, but just because it was invalid (see
https://github.com/bitcoin/bitcoin/pull/19195#discussion_r448020762), not
because it was implemented.
This is a backport of core#19425 [1/3]
https://github.com/bitcoin/bitcoin/pull/19425/commits/3fbbb9a6403a86fbed3d5d9f7939998922593377
Test Plan: ninja all check-all
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D11418