Fix some std::move issues

Summary:
These moves are either:

• copies because the variable being moved is const
• references because the function parameter the var is moved to is a reference

Either fix by removing the constness or removing the move.
For the places where the move is removed, there is no performance impact as it was not working anyway.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D16288