283863a test-network: use raw strings for regexes with backslashes

Authored and Committed by mrc0mmand 2 years ago
    test-network: use raw strings for regexes with backslashes
    
    It currently works because `\(` and `\)` are not valid escape sequences,
    so they're not treated differently. Using raw strings (or double
    backslashes) is a more correct solution.