tests] Rename wallet_* functional tests
Summary:
Rename only
Partial backport of core PR11774 (commit 90600bc)
Depends on D2364
Test Plan:
./test/functional/test_runner.py --extended
Reviewers: #bitcoin_abc, deadalnix
Reviewed By: #bitcoin_abc, deadalnix
Subscribers: teamcity, schancel
Differential Revision: https://reviews.bitcoinabc.org/D2378