The variable `oicmp`, which holds the original ("quoted packet") ICMP packet in a structured way, did not had a copy of the original ICMP packet obtained from the raw data.
The code was accidentally removed in 20b41303140eee4dfb896558fb83600c5f013d39.
Bring it back. While here, apply `style(9)` to this section of the code.
Additionally, add two regression tests that do not use the verbose flag, so this code path can be reached:
1. Respond with a proper ICMP destination host unreachable packet.
2. Respond with a doctored ICMP destination host unreachable packet, that has the ICMP Identifier field modified (+1 bit).
Without the code that was accidentally removed, test 1 should fail.
Reported by: Coverity Scan, cy
CID:
Fixes: 20b41303140eee4dfb896558fb83600c5f013d39
MFC after: 1 week