Merge #9949: [bench] Avoid function call arguments which are pointers to uninitialized values

Summary:
218d915 [bench] Avoid function call arguments which are pointers to uninitialized values (practicalswift)

Tree-SHA512: 68d62e9442094f171433291b7f13dba20fc7ead5fd7f2292e1eb97ae51aa2345d40224c4a65c2e5d3552802b3cd0f675a82b6181cf5b77e964355650b25089f0

Backport of Core PR9949
https://github.com/bitcoin/bitcoin/pull/9949

Test Plan:

make check

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

Reviewed By: jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D3324