add a new ci job to fuzz sp-arithmetic

[altaua]

as requested in https://github.com/paritytech/ci_cd/issues/761

[altaua]

Using a private fork of honggfuzz-rs for now until upstream merges rust-fuzz/honggfuzz-rs#81 and rust-fuzz/honggfuzz-rs#82.

[ggwpez]

Okay thanks! The failing fuzzers look good:

Maybe you can still run it in a quiet mode, so that the log output is a bit shorter? I did not yet fix the normalize fuzzer, so could be that it still fails after #13659.
Maybe we can make the check optional for now, if it is not fixed before this merges.

[altaua]

Maybe you can still run it in a quiet mode, so that the log output is a bit shorter? I did not yet fix the normalize fuzzer, so could be that it still fails after #13659.

Yeah, the log is unpleasantly noisy for sure. Unfortunately, --quiet also hides log messages about crashes encountered during fuzzing, and does /not/ hide the irrelevant internal hongfuzz warning input_getNext():129 No useful files in the input directory.

I didn't want the logs to be empty except for some totally expected warnings, so I chose to leave the job in verbose mode.

Maybe we can make the check optional for now, if it is not fixed before this merges.

Yep, I've tagged it with allow_failure: true, it won't block merges.

[ggwpez]

Thanks!

(Approving from Runtime point of view)

[altaua]

We'll hold off on merging this PR until #13660 lands; beyond that, it's ready.

[ggwpez]

It merged.

bot rebase

[paritytech-processbot]

Rebased