[qa] make create_confirmed_utxos calculate fees
Summary: As per title. Depends on D1632
Test Plan: ./test/functional/test_runner.py
Reviewers: #bitcoin_abc, jasonbcox
Reviewed By: #bitcoin_abc, jasonbcox
Subscribers: jasonbcox, teamcity
Differential Revision: https://reviews.bitcoinabc.org/D1633