[Backport]util: Filter control characters out of log messages

Summary:
Belts and suspenders: make sure outgoing log messages don't contain
potentially suspicious characters, such as terminal control codes.

This escapes control characters except newline ('\n') in C syntax.
It escapes instead of removes them to still allow for troubleshooting
issues where they accidentally end up in strings.

Backport of Bitcoin Core PR17095

Test Plan: ninja && ninja check

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, deadalnix

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D7517