[validation] Make script error messages uniform for parallel/single validation

Summary:
This makes the debug output mostly the same for -par=1 and parallel validation runs. Of course,
parallel validation is non-deterministic in what error it may encounter first if there are
multiple issues. Also, the way certain script-related and non-script-related checks are
performed differs between the two modes still, which may result in discrepancies.

This is a partial backport of core#31112
https://github.com/bitcoin/bitcoin/pull/31112/commits/146a3d542683ddb89a31104f5211dfc757d1dafb

Depends on D18876

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D18877