Extract CWallet::MarkInputsDirty

Summary:
To avoid repeated implementations.

Partial backport of Core PR13651
https://github.com/bitcoin/bitcoin/pull/13651/commits/b7f565094296b727d1309418d3a284d942f15f11

Depends on D4674

Test Plan:

make check
test_runner.py

Reviewers: deadalnix, Fabien, jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Reviewed By: jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D4675