validation, test, bench: make CScriptCheck and prevector swap member functions noexcept

Summary:
Reason:
A swap must not fail; when a class has a swap member function, it should be declared noexcept.
https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c84-a-swap-function-must-not-fail

This is a backport of core#25017

Test Plan: ninja all check-all bench-bitcoin bitcoin-fuzzers

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13188