Update to AFL++

[mschessler]

I'm not sure if there was a special reason to remain on AFL instead of AFL++, but the latter should be better in any metric. It therefore would help to have it as a default.

Done:

• updated to AFL++ v4.30c
• updated documentation
• run Github action
• tested Fuzzer.Run, Fuzzer.OutOfProcess.Run and afl-tmin

What exactly was the reason behind Fuzzer.RunOnce, only for afl-tmin?
It does not work with AFL++ but I have no problem minimizing my crashes with both Fuzzer.Run and Fuzzer.OutOfProcess.Run.
Could it maybe be removed ? Or are there edge-cases where we need it ?

[mschessler]

Default bitmap size changed from

#define MAP_SIZE_POW2 16
#define MAP_SIZE (1 << MAP_SIZE_POW2)

in AFL to

#define DEFAULT_SHMEM_SIZE (8 * 1024 * 1024)

in AFL++

private const int MapSize = 1 << 16; in Fuzzer.cs probably would need adjustment ?