test(output): cover bad host exit status

[Komzpa]

Summary

• add regression coverage for failed hostname resolution in non-interactive output modes
• verify --csv, --raw, --report, --xml, and --json when available all return non-zero and print the resolver error

Fixes #294.

The current code already exits non-zero in these cases; this keeps the historical --csv/--raw/--json failure mode covered.

Tests

• git diff --check
• ./bootstrap.sh && ./configure --without-gtk --without-jansson && make -j "$(nproc)"
• sudo python3 ./test/cmdparse.py

[rewolff]

FYI: You're issuing patches at a higher rate than what I can check-and-approve. So I have to prioritize a few other things now.

[Komzpa]

@rewolff please do not be stressed about it, there is no rush, and thanks for taking the time to review and merge the things you merged already. I hope the patches are useful; but if ticket was there since 2017 it can probably wait a bit longer so everyone can have a balanced life.