Merge #10845: Remove unreachable code

Summary:
41bf1598f Remove unreachable code (practicalswift)

Pull request description:

Remove unreachable code.

Tree-SHA512: 2ae94035f693b1ac73b1587eafcc646602a185f6d2b8a24a05939b43235b331c9e6f369ad2e8208624a47c920e989413c6a89ab9b608add5b7be4ebefae2a796

Backport of Core PR10845
https://github.com/bitcoin/bitcoin/pull/10845

Test Plan:

make check
test_runner.py

Reviewers: deadalnix, Fabien, jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Reviewed By: jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D3658