refactor: Use member initializers in CCheckQueue
refactor: Use member initializers in CCheckQueue

Summary:
This is a backport of [[https://github.com/bitcoin/bitcoin/pull/18710 | core#18710]] [1/4]
https://github.com/bitcoin/bitcoin/pull/18710/commits/0ef938685b5c079a6f5a98daf0e3865d718d817b

Test Plan: `ninja all check-all`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10985

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