Start using a dictionary for fuzzing (see:
https://llvm.org/docs/LibFuzzer.html#dictionaries).
Remove some dead code.
Fuzzing with debug enabled is not usually a great idea (from performance
POV). Keep the code since it might be useful while debugging.
Load some custom configuration (like in the unit tests) and factorize some
(fuzzing) common code.
There is no way to pass file paths to the fuzzers as parameters. The safe
solution seems to be to load them from the process working dir. Anyway,
missing file is not a blocking error.
Remove some dead code (found looking at the coverage report)
We don't need specific targets to reproduce fuzzing issues.
After all, calling `./fuzz/fuzz_process_packet_with_main $ARTIFACT_FILE`
is equivalento to `./fuzz/fuzz_process_packet $ARTIFACT_FILE`
QUIC packets are encrypted/obfuscated; that means that we need to
decrypt them before parsing the real (TLS) message.
Fuzzing is not effective here, since a random buffer is hardly a valid
encrypted QUIC packet.
Add a new fuzzer, testing *decrypted* QUIC packets.
Add a basic corpus.
Fix a few bugs already found by this fuzzer.
