Fix checkqueue_tests use-after-scope

Summary:
This reverts the change to checkqueue_tests from D3146 to reapply the
fix from PR12477 (see D3566).

Test Plan:
With ASAN enabled:

src/test/test_bitcoin -t checkqueue_tests

Reviewers: #bitcoin_abc, deadalnix, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Differential Revision: https://reviews.bitcoinabc.org/D3598