Change ismine to take a CWallet instead of CKeyStore

Summary:
This is a partial backport of Core PR16226 : https://github.com/bitcoin/bitcoin/pull/16226/commits/e61de6306fd89fe9aae90253062e7b1b20343f8a

Depends on D6407

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D6408